Поспєлов, С.В. 2012. Peculiarities of development of inflorescences and flowering of purple coneflower (Echinacea purpurea (L.) Moench) and pale coneflower (Echinacea pallida (Nutt.) Nutt.) in the foreststeppe of Ukraine. Scientific Progress & Innovations. 3 (Sep. 2012), 35–43. DOI:https://doi.org/10.31210/visnyk2012.03.07.