Son, N., 		Hoa, N., & 		Dung, L.
(2011).
 Composition of bird species in Huu Lien Nature Reserve, Lang Son province.
<em>VNU Journal Of Science: Earth And Environmental Sciences, 27</em>(1).
Retrieved from <a href="https://js.vnu.edu.vn/EES/article/view/1496" target="_new">https://js.vnu.edu.vn/EES/article/view/1496</a>