Kawin Pla-on. 2005. Tropical watermeal (Wolffia globosa (Roxb) Hartog & Plas) as bioindicator of zinc and copper contamination in natural water presources. Field of Study Appropriate Technology for Resources and Environmental Development, Mahidol University;

Kawin Pla-on. Tropical watermeal (Wolffia globosa (Roxb) Hartog & Plas) as bioindicator of zinc and copper contamination in natural water presources. . Bangkok:Mahidol University, 2005.

Kawin Pla-on. (2005) Tropical watermeal (Wolffia globosa (Roxb) Hartog & Plas) as bioindicator of zinc and copper contamination in natural water presources . Mahidol University/Bangkok.