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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">kurskvest</journal-id><journal-title-group><journal-title xml:lang="ru">Человек и его здоровье</journal-title><trans-title-group xml:lang="en"><trans-title>Humans and their health</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">1998-5746</issn><issn pub-type="epub">1998-5754</issn><publisher><publisher-name>Kursk State Medical University</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.21626/vestnik/2026-2/11</article-id><article-id custom-type="edn" pub-id-type="custom">ZEVMYT</article-id><article-id custom-type="elpub" pub-id-type="custom">kurskvest-1577</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ФАРМАЦЕВТИЧЕСКИЕ НАУКИ</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>PHARMACEUTICAL SCIENCES</subject></subj-group></article-categories><title-group><article-title>Накопление калия-40 в лекарственном растительном сырье флоры Воронежской области</article-title><trans-title-group xml:lang="en"><trans-title>Accumulation of potassium-40 in medicinal plant raw materials of flora of Voronezh region</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-0766-3881</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Дьякова</surname><given-names>Нина Алексеевна</given-names></name><name name-style="western" xml:lang="en"><surname>Dyakova</surname><given-names>Nina A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>д-р фарм. наук, доцент, доцент кафедры фармацевтической технологии, ВГУ, г. Воронеж</p></bio><bio xml:lang="en"><p>Dr. Sci. (Med.), Associate Professor, Assistant Professor, Department of Pharmaceutical Technology, VSU, Voronezh, Russian Federation</p></bio><email xlink:type="simple">ninochka_v89@mail.ru</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Воронежский государственный университет (ВГУ)</institution><country>Россия</country></aff><aff xml:lang="en"><institution>Voronezh State University (VSU)</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2026</year></pub-date><pub-date pub-type="epub"><day>07</day><month>07</month><year>2026</year></pub-date><volume>29</volume><issue>2</issue><fpage>81</fpage><lpage>90</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Дьякова Н.А., 2026</copyright-statement><copyright-year>2026</copyright-year><copyright-holder xml:lang="ru">Дьякова Н.А.</copyright-holder><copyright-holder xml:lang="en">Dyakova N.A.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://www.kursk-vestnik.ru/jour/article/view/1577">https://www.kursk-vestnik.ru/jour/article/view/1577</self-uri><abstract><p>Проблема накопления радионуклидов в лекарственном растительном сырье является многогранной и требует глубокого понимания физико-химических и биологических механизмов, лежащих в основе их миграции в системе «почва - растение - лекарственный препарат». Поэтому необходим региональный мониторинг по изучению радиоэкологической обстановки, включая анализ не только техногенных, но и природных радионуклидов. Цель - провести изучение особенностей накопления в лекарственном растительном сырье флоры Воронежской области калия-40. Материалы и методы. Для проведения исследования был отобран ряд широко распространенных видов, включающих траву горца птичьего ( Polygonum aviculare L.), полыни горькой ( Artemisia absinthium L.), тысячелистника обыкновенного ( Achillea millefolium L.), пустырника пятилопастного ( Leonurus quinquelobatus Gilib.), листья подорожника большого ( Plantago major L.) и крапивы двудомной ( Urtica dioica L.), цветки липы сердцевидной ( Tilia cordata Mill.) и пижмы обыкновенной ( Tanacetum vulgare L.), корни одуванчика лекарственного (Taraxacum officinale F.H. Wigg) и лопуха большого (Arctium lappa L.). Параллельно проводился забор образцов почвы с глубины 0-20 см для оценки фонового содержания радионуклидов. Измерения удельной активности калия-40 в почвенных и растительных образцах выполнялись с использованием спектрометра МКГБ-01 «РАДЭК». Результаты. Статистический анализ выявил наличие сильной положительной корреляции между удельной активностью радионуклида в почве и в растительном сырье. Это позволяет утверждать, что основным путем попадания в сырье калия-40 является его поглощение из почвы. При увеличении удельной активности калия-40 в почве возрастала его удельная активность в растительном сырье. Установлена неравномерность распределения радиоизотопа в различных органах растений. Калий-40 в наибольшей концентрации аккумулируется в листьях и травах анализируемых видов. Заключение. Результаты исследования демонстрируют необходимость учета региональных особенностей и промышленной истории местности при оценке качества лекарственного растительного сырья, в частности, в отношении природных радионуклидов, а также могут быть использованы при разработке региональных норм его качества.</p></abstract><trans-abstract xml:lang="en"><p>The problem of accumulation of radionuclides in medicinal plant raw materials is multifaceted and requires a deep understanding of the physicochemical and biological mechanisms underlying their migration in the soil-plant-drug system. Therefore, regional monitoring is needed to study the radioecological situation, including the analysis of not only man-made, but also natural radionuclides. Objective - to study the peculiarities of accumulation in plant resources of the flora of the Voronezh region of potassium-40. Materials and methods. A number of widespread species were selected for the study, including bird highlander grass (Polygonum aviculare L.), wormwood (Artemisia absinthium L.), yarrow (Achillea millefolium L.), motherwort five-lobed (Leonurus quinquelobatus Gilib.), plantain leaves large (Plantago major L.) and dioecious nettles (Urtica dioica L.), heart-shaped linden flowers (Tilia cordata Mill.) and common tansy (Tanacetum vulgare L.), the roots of dandelion medicinal (Taraxacum officinale F.H.Wigg) and burdock large (Arctium lappa L.). In parallel, soil samples were taken from a depth of 0-20 cm to assess the background content of radionuclides. Measurements of potassium-40 specific activity in soil and plant samples were performed using the RADEK MKGB-01 spectrometer. Results. Statistical analysis revealed the presence of a strong positive correlation between the specific activity of the radionuclide in the soil and in plant raw materials. This allows us to assert that the main way potassium-40 gets into the raw materials is its absorption from the soil. With an increase in the specific activity of potassium-40 in the soil, its specific activity in plant raw materials increased. The unevenness of the distribution of the radioisotope in various plant organs has been established. Potassium-40 is most concentrated in the leaves and grasses of the analyzed species. Conclusion. The results of the study demonstrate the need to take into account regional features and industrial history of the area when assessing the quality of medicinal plant raw materials, in particular, in relation to natural radionuclides, and can also be used in the development of regional standards for its quality.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>калий-40</kwd><kwd>Воронежская область</kwd><kwd>коэффициенты накопления</kwd><kwd>лекарственное растительное сырье</kwd><kwd>коэффициенты корреляции</kwd></kwd-group><kwd-group xml:lang="en"><kwd>potassium-40</kwd><kwd>Voronezh region</kwd><kwd>accumulation coefficients</kwd><kwd>medicinal plant raw materials</kwd><kwd>correlation coefficients</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Dyakova N., Gaponov S., Slivkin A., Chupandina E. Accumulation of artificial and natural radionuclides in medicinal plant material in the Central Black Soil Region of Russia. Adv Biol Sci Res. 2019;7:94-96. DOI: 10.2991/isils-19.2019.22</mixed-citation><mixed-citation xml:lang="en">Dyakova N., Gaponov S., Slivkin A., Chupandina E. Accumulation of artificial and natural radionuclides in medicinal plant material in the Central Black Soil Region of Russia. Adv Biol Sci Res. 2019;7:94-96. DOI: 10.2991/isils-19.2019.22</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Jablonskikh L.A. Content and vertical distribution of heavy metals and radionuclides in hydromorphic soils of the forest steppe. Eurasian Soil Sci. 1999;32(4):394-403.</mixed-citation><mixed-citation xml:lang="en">Jablonskikh L.A. Content and vertical distribution of heavy metals and radionuclides in hydromorphic soils of the forest steppe. Eurasian Soil Sci. 1999;32(4):394-403.</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Dyakova N.A. Study of accumulation of natural and artificial radioisotopes by medicinal plant raw materials on the example of plantain leaves of large flora of urbanized territories of the Central Black Earth Region.Russ J Bioorg Chem. 2025;51(7):3056-3067. DOI: 10.1134/S106816202515018X.</mixed-citation><mixed-citation xml:lang="en">Dyakova N.A. Study of accumulation of natural and artificial radioisotopes by medicinal plant raw materials on the example of plantain leaves of large flora of urbanized territories of the Central Black Earth Region.Russ J Bioorg Chem. 2025;51(7):3056-3067. DOI: 10.1134/S106816202515018X.</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Богачев А.В. Миграция 137Cs и калия в системе «почва-растение». Факты, закономерности, гипотезы: учебное пособие. Москва: Институт проблем безопасного развития атомной энергетики РАН; 1997. 35 с.</mixed-citation><mixed-citation xml:lang="en">Bogachev A.V. Migration of ¹³Cs and potassium in the soil-plant system. Facts, patterns, hypotheses: a study guide. Moscow: Nuclear Safety Institute of the Russian Academy of Sciences; 1997. 35 p. (in Russ.)</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Государственная фармакопея Российской Федерации. Издание XIV. Том 4. Москва: ФЭМБ, 2018 1883 с.</mixed-citation><mixed-citation xml:lang="en">State Pharmacopoeia of the Russian Federation. Edition XIV. Volume 4. Moscow: FEMB, 2018 1883p. (in Russ.)</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">European Directorate for the Quality of Medicines &amp; HealthCare. European Pharmacopoeia. 10th ed. Strasbourg: EDQM; 2019: 4120.</mixed-citation><mixed-citation xml:lang="en">European Directorate for the Quality of Medicines &amp; HealthCare. European Pharmacopoeia. 10th ed. Strasbourg: EDQM; 2019: 4120.</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Dyakova N.A., Lyubashevsky D.E., Chupandina E.E., Pisklyukov A.A. Study of natural and artificial radionuclides accumulation by medicinal plant raw materials on the example of nettle leaves of Urtica dioica. Biol Trace Elem Res. 2025;(7). DOI: 10.1007/s12011-025-04702-1.</mixed-citation><mixed-citation xml:lang="en">Dyakova N.A., Lyubashevsky D.E., Chupandina E.E., Pisklyukov A.A. Study of natural and artificial radionuclides accumulation by medicinal plant raw materials on the example of nettle leaves of Urtica dioica. Biol Trace Elem Res. 2025;(7). DOI: 10.1007/s12011-025-04702-1.</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Dyakova N.A. Accumulation of natural and artificial radionuclides by medicinal plant raw materials using nettle leaves as an example. Pharm Chem J. 2024;58(3):468-477. DOI: 10.1007/s11094-024-03166-2.</mixed-citation><mixed-citation xml:lang="en">Dyakova N.A. Accumulation of natural and artificial radionuclides by medicinal plant raw materials using nettle leaves as an example. Pharm Chem J. 2024;58(3):468-477. DOI: 10.1007/s11094-024-03166-2.</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Neverova O.A., Egorova I.N. Assessment of radionuclide pollution of Rosa majalis Herrm fruits in the circumstances of the anthropologically disordered Kuznetsk basin areas. Adv Environ Biol. 2014;8(13):414-418.</mixed-citation><mixed-citation xml:lang="en">Neverova O.A., Egorova I.N. Assessment of radionuclide pollution of Rosa majalis Herrm fruits in the circumstances of the anthropologically disordered Kuznetsk basin areas. Adv Environ Biol. 2014;8(13):414-418.</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Парамонова Т.А., Романцова Н.А. Сравнительный анализ поступления цезия-137 и калия-40 в травянистую растительность на радиоактивно загрязненной территории Тульской области. Живые и биокосные системы. 2013;(5):4-9.EDN: UYNDLD.</mixed-citation><mixed-citation xml:lang="en">Paramonova T.A., Romantsova N.A.Comparative analysis of cesium-137 and potassium-40 input into herbaceous vegetation on radioactively contaminated territory of Tula region. Zhivye i biokosnye sistemy. 2013;(5):4-9. (in Russ.). EDN: UYNDLD.</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Ryzhakova N.K., Babeshina L.G., Kondratyeva A.G., Sechnaya D.Y. Contents of macro-, microelements and long-lived radionuclides in the medicinal plants belonging to the wetland community of Siberian region, Russia. Phytochem Lett. 2017;22:280-286. DOI: 10.1016/j.phytol.2017.10.001.</mixed-citation><mixed-citation xml:lang="en">Ryzhakova N.K., Babeshina L.G., Kondratyeva A.G., Sechnaya D.Y. Contents of macro-, microelements and long-lived radionuclides in the medicinal plants belonging to the wetland community of Siberian region, Russia. Phytochem Lett. 2017;22:280-286. DOI: 10.1016/j.phytol.2017.10.001.</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Dyakova N.A., Slivkin A.I., Trineeva O.V. From assessment of radionuclide contamination in herbal medicine raw material of Voronezh region to issues concerning standardization of natural radionuclides. Pharm Chem J. 2022;56(8):1082-1086. DOI: 10.1007/s11094-022-02757-1.</mixed-citation><mixed-citation xml:lang="en">Dyakova N.A., Slivkin A.I., Trineeva O.V. From assessment of radionuclide contamination in herbal medicine raw material of Voronezh region to issues concerning standardization of natural radionuclides. Pharm Chem J. 2022;56(8):1082-1086. DOI: 10.1007/s11094-022-02757-1.</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Бекман И.Н. Радиоэкология и экологическая радиохимия. Москва; 2018. 400 с.</mixed-citation><mixed-citation xml:lang="en">Bekman I.N. Radioecology and environmental radiochemistry. Moscow; 2018. 400 p. (in Russ.)</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">İsel P., Sahin L., Hafızoğlu N., Ganioğlu E., Mülayim A. Natural and artificial radioactive pollution in sediment and soil samples of the Bosphorus, Istanbul. Environ Sci Pollut Res Int. 2023;30(27): 70937-70949. DOI: 10.1007/s11356-023-27455-7.</mixed-citation><mixed-citation xml:lang="en">İsel P., Sahin L., Hafızoğlu N., Ganioğlu E., Mülayim A. Natural and artificial radioactive pollution in sediment and soil samples of the Bosphorus, Istanbul. Environ Sci Pollut Res Int. 2023;30(27): 70937-70949. DOI: 10.1007/s11356-023-27455-7.</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Maystrenko T., Rybak A. Radium uptake by earthworms Eisenia fetida after exposure to contaminated soil. J Environ Radioact. 2023;257:107085. DOI: 10.1016/j.jenvrad.2022.107085.</mixed-citation><mixed-citation xml:lang="en">Maystrenko T., Rybak A. Radium uptake by earthworms Eisenia fetida after exposure to contaminated soil. J Environ Radioact. 2023;257:107085. DOI: 10.1016/j.jenvrad.2022.107085.</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Kozłowska B., Walencik A., Dorda J., Zipper W. Radioactivity of dumps in mining areas of the Upper Silesian Coal Basin in Poland. EPJ Web Conf. 2012;24:05006. DOI: 10.1051/epjconf/20122405006.</mixed-citation><mixed-citation xml:lang="en">Kozłowska B., Walencik A., Dorda J., Zipper W. Radioactivity of dumps in mining areas of the Upper Silesian Coal Basin in Poland. EPJ Web Conf. 2012;24:05006. DOI: 10.1051/epjconf/20122405006.</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Wang X., Feng Q., Sun R., Liu G. Radioactivity of Natural Nuclides (40K, 238U, 232Th, 226Ra) in Coals from Eastern Yunnan, China. Minerals. 2015;5: 637-646. DOI: 10.3390/min5040513.</mixed-citation><mixed-citation xml:lang="en">Wang X., Feng Q., Sun R., Liu G. Radioactivity of Natural Nuclides (40K, 238U, 232Th, 226Ra) in Coals from Eastern Yunnan, China. Minerals. 2015;5: 637-646. DOI: 10.3390/min5040513.</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Pak Y.N., Pak D.Y., Ponomaryova M.V., Baizbayev M.B., Zhelayeva N.V. Radioactivity of coal and its combustion wastes. Coke Chem. 2018;61(5):188-192.</mixed-citation><mixed-citation xml:lang="en">Pak Y.N., Pak D.Y., Ponomaryova M.V., Baizbayev M.B., Zhelayeva N.V. Radioactivity of coal and its combustion wastes. Coke Chem. 2018;61(5):188-192.</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Kuzmanović P., Srećković M., Lužaić T. Quantification of 40K and 137Cs in food packaging materials and radiation risk assessment due to their potential migration into food. Sci Total Environ. 2026;1023:181642. DOI: 10.1016/j.scitotenv.2026.181642.</mixed-citation><mixed-citation xml:lang="en">Kuzmanović P., Srećković M., Lužaić T. Quantification of 40K and 137Cs in food packaging materials and radiation risk assessment due to their potential migration into food. Sci Total Environ. 2026;1023:181642. DOI: 10.1016/j.scitotenv.2026.181642.</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Lee J.W., Lee S.D., Min H.B., Han C.H., Kim K.P. Assessment of K-40 and Cs-137 radioactivity concentrations and annual effective dose due to ingestion of staple foods in South Korea. Appl Radiat Isot. 2025;226:112246. DOI: 10.1016/j.apradiso.2025.112246.</mixed-citation><mixed-citation xml:lang="en">Lee J.W., Lee S.D., Min H.B., Han C.H., Kim K.P. Assessment of K-40 and Cs-137 radioactivity concentrations and annual effective dose due to ingestion of staple foods in South Korea. Appl Radiat Isot. 2025;226:112246. DOI: 10.1016/j.apradiso.2025.112246.</mixed-citation></citation-alternatives></ref><ref id="cit21"><label>21</label><citation-alternatives><mixed-citation xml:lang="ru">Hampton C.R., Broadley M.R., White P.J. Short review: the mechanisms of radiocaesium uptake by Arabidopsis roots. Nukleonika. 2005;50:S3-S8.</mixed-citation><mixed-citation xml:lang="en">Hampton C.R., Broadley M.R., White P.J. Short review: the mechanisms of radiocaesium uptake by Arabidopsis roots. Nukleonika. 2005;50:S3-S8.</mixed-citation></citation-alternatives></ref><ref id="cit22"><label>22</label><citation-alternatives><mixed-citation xml:lang="ru">Živković M.P., Alshehri A.H.D., Abas Abdullah A., Krstić D.Ž., Salem F.A., Wais T.Y. Dietary exposure to natural and artificial radionuclides through cereal, legume, seed, and nut products: measurement and uptake assessment. J Environ Radioact. 2026;291:107860. DOI:10.1016/j.jenvrad.2025.107860.</mixed-citation><mixed-citation xml:lang="en">Živković M.P., Alshehri A.H.D., Abas Abdullah A., Krstić D.Ž., Salem F.A., Wais T.Y. Dietary exposure to natural and artificial radionuclides through cereal, legume, seed, and nut products: measurement and uptake assessment. J Environ Radioact. 2026;291:107860. DOI:10.1016/j.jenvrad.2025.107860.</mixed-citation></citation-alternatives></ref><ref id="cit23"><label>23</label><citation-alternatives><mixed-citation xml:lang="ru">Saleh D.S., Salh H., Smail J.M., Ahmad S.T. A review of annual effective dose from ingesting 226Ra, 232Th, and 40K in rice across different countries. Isotopes Environ Health Stud. 2025;61(3):298-309. DOI: 10.1080/10256016.2025.2488297.</mixed-citation><mixed-citation xml:lang="en">Saleh D.S., Salh H., Smail J.M., Ahmad S.T. A review of annual effective dose from ingesting 226Ra, 232Th, and 40K in rice across different countries. Isotopes Environ Health Stud. 2025;61(3):298-309. DOI: 10.1080/10256016.2025.2488297.</mixed-citation></citation-alternatives></ref><ref id="cit24"><label>24</label><citation-alternatives><mixed-citation xml:lang="ru">Методические рекомендации МР 2.6.1/2.3.7.0216-20. Радиохимическое определение удельной активности природных радионуклидов в пробах пищевой продукции, почвы, других объектов окружающей среды и биопробах. Москва; 2020.URL: https://www.garant.ru/products/ipo/prime/doc/74835247/</mixed-citation><mixed-citation xml:lang="en">Methodological recommendations MR 2.6.1/2.3.7.0216-20. Radiochemical determination of specific activity of natural radionuclides in food products, soil, other environmental objects and bioassays.  Förster E, Rönz E. Methods of correlation and regression analysis. Moscow; 1983. 304 p. (in Russ.)</mixed-citation></citation-alternatives></ref><ref id="cit25"><label>25</label><citation-alternatives><mixed-citation xml:lang="ru">Фёрстер Э., Рёнц Э. Методы корреляционного и регрессионного анализа. Москва; 1983. 304 с.</mixed-citation><mixed-citation xml:lang="en">Фёрстер Э., Рёнц Э. Методы корреляционного и регрессионного анализа. Москва; 1983. 304 с.</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
