Việt Nam

 http://www.nhandan.com.vn/tinbai/?top=41&sub=72&article=94755

 http://hanoitv.vn/tintuc/vn/detail.asp?CatID=4&NewsID=20154

 http://vietnamnet.vn/khoahoc/tdsk/2007/05/697594/

 http://www.hanoimoi.com.vn/vn/48/130732/

 National Geographic