http://agriviet.com/home/showthread.php?t=19535

http://www.yeumoitruong.com/home/index.php?option=com_content&view=article&id=1057:-nha-rua-vn-cuc-phng&catid=37:bo-tn-thien-nhien&Itemid=272

http://www.ruffordsmallgrants.org/rsg/Projects/TimMcCormack