APA
NATIONAL PARKS, . (1989). Proceedings of the botanic gardens 130th Anniversary seminar. SINGAPORE: SINGAPORE BOTANIC GARDENS.
Chicago
NATIONAL PARKS, . 1989. Proceedings of the botanic gardens 130th Anniversary seminar. SINGAPORE: SINGAPORE BOTANIC GARDENS.
Harvard
NATIONAL PARKS, . (1989). Proceedings of the botanic gardens 130th Anniversary seminar. SINGAPORE: SINGAPORE BOTANIC GARDENS.
MLA
NATIONAL PARKS, . Proceedings of the botanic gardens 130th Anniversary seminar. SINGAPORE: SINGAPORE BOTANIC GARDENS. 1989.