Начичко, В. О. “Diagnostic Features of Representatives of Thymus Sect. Serpyllum and T. Sect. Marginati (Lamiaceae) and Guidance for Their Herborization”. The Journal of V.N.Karazin Kharkiv National University. Series «Biology», Vol. 25, 1, pp. 77-89, https://periodicals.karazin.ua/biology/article/view/5519.