Soudzilovskaya, N., and V. Onipchenko. “Influence of Soil Nutrient Availability on Generative Production in an Alpine Heath, the North-Western Caucasus”. Oecologia Montana, Vol. 10, no. 1-2, Dec. 2001, pp. 29-37, http://om.vuvb.uniza.sk/index.php/OM/article/view/130.