Павлик, О. М., and Д. О. Вакуленко. “Features of Uneasiness at Emotionally Steady and Unstable Kickboxing”. Slobozhanskyi Herald of Science and Sport, no. 4(27), Dec. 2011, pp. 266-8, https://journals.uran.ua/index.php/1991-0177/article/view/30399.