Mishchenko, O.V., E.A. Golovko, and S.V. Pospelov. “The Peculiarities of Allelopathic Activity of Echinacea Purpurea of the First and Second Years of Vegetation”. Plant Introduction 28 (December 1, 2005): 88-92. Accessed October 19, 2026. http://www.plantintroduction.org/index.php/pi/article/view/924.