ECKSTEIN, R. Lutz, Norbert HÖLZEL a
Jiří DANIHELKA. Biological Flora of Central Europe: Viola elatior, V. pumila and V. stagnina.
Perspectives in Plant Ecology, Evolution and Systematics. Zürich: Urban & Fischer, 2006, roč. 8, č. 1, s. 45-66, 21 s. ISSN 1433-8319.