Yen Nhi N H and Preston T R 2011: The growth and economics of integrated culture of Tilapia (Oreochomis niloticus) and Common carp (Ciprinus carpio) in an indoor intensive system with earthworms as feed and in natural ponds fertilized with biodigester effluent and supplemented with duckweed. Livestock Research for Rural Development. Volume 23, Article #161. Retrieved , from http://www.lrrd.org/lrrd23/7/nhi23161.htm