• Agu Aarna 70Eesti NSV Teaduste Akadeemia toimetised. Keemia = Proceedings of Academy of Sciences of the Estonian SSR. Chemistry = Известия Академии наук Эстонской ССР. Химия1985 / lk. 307-309 https://www.etera.ee/zoom/19218/view?page=1&p=separate&tool=info&view=0,0,2465,3986 https://www.ester.ee/record=b1264984*est