Ahn , Eun-Young. 2007. Записки Горного института 170 (2), 42-45. https://pmi.spmi.ru/pmi/article/view/7710.

Ahn , Eun-Young. 2007. “Economic Impact Analysis of National Natural Gas Storage”. Journal of Mining Institute 170 (2), 42-45. https://pmi.spmi.ru/pmi/article/view/7710.