Aloyan, P. G., and H. P. Guyumjyan. “ALUMINIC-RARE-EARTH-PRECIOUS METALS FORMATION IN NEPHELINE SYENITES OF ARMENIA”. Proceedings of the YSU C: Geological and Geographical Sciences, vol. 45, no. 2 (225), July 2011, pp. 10-16, doi:10.46991/PYSU:C/2011.45.2.010.