Reference

Olga V. Yurtseva, Maria S. Levina, Elena E. Severova, Alexey V. Troitsky (2012): Morphology and taxonomy of Polygonum cognatum Meisn., P. alpestre C. A. Mey. and allied taxa from Central Asia and the Caucasus (Polygonaceae). – Wulfenia – 19: 141 - 180.