Синюгіна [Mariya Sinyugina] М. Б. “Change of Indicators Rheography at the Qualified Athletes-Swimmers When Overcoming a Marathon Distance”. Slobozhanskyi Herald of Science and Sport, no. 5(38), Dec. 2013, pp. 243-7, https://journals.uran.ua/index.php/1991-0177/article/view/19112.