De Guzman, C. C. (1996). The essential oils research and development program (EORDP): Linking its endeavors to essential oils production in the Philippines. Philippine Agricultural Scientist, The (Formerly the Philippine Agriculturist).
Chicago-referens (17:e uppl.)De Guzman, Constancio C. "The Essential Oils Research and Development Program (EORDP): Linking Its Endeavors to Essential Oils Production in the Philippines." Philippine Agricultural Scientist, The (Formerly the Philippine Agriculturist) 1996.
MLA-referens (9:e uppl.)De Guzman, Constancio C. "The Essential Oils Research and Development Program (EORDP): Linking Its Endeavors to Essential Oils Production in the Philippines." Philippine Agricultural Scientist, The (Formerly the Philippine Agriculturist), 1996.