©2013 National Research Council of Thailand
Niwat Keawpradub. 1998. Studies on the bioactivity and alkaloids of three Thai Alstonia species. Department of Pharmacy, University of London;
Niwat Keawpradub. (1998) Studies on the bioactivity and alkaloids of three Thai Alstonia species . University of London/London.
Niwat Keawpradub. Studies on the bioactivity and alkaloids of three Thai Alstonia species. . London:University of London, 1998.
Niwat Keawpradub. (1998) Studies on the bioactivity and alkaloids of three Thai Alstonia species . University of London/London.