Phương, Nguyễn. “VỀ ĐÁ VÔI TRẮNG KHU VỰC LỤC YÊN - YÊN BÁI”. <i>Vietnam Journal of Earth Sciences</i> 27, no. 2 (March 27, 2005): 150–154. Accessed April 2, 2026. https://cip.vast.vn/jse/article/view/9407.