1. Pollination biology of Calypso bulbosa var. occidentalis (Orchidaceae): a food-deceptive system;Ackerman;Mardoño,1981
2. Coping with the epiphytic existence: pollination strategies;Ackerman;Selbyana,1986
3. An orchid Flora of Puerto Rico and the Virgin Islands;Ackerman;Memoirs of the New York Botanical Gardens,1995
4. Epiphyte host specificity of Encyclia krugii, a Puerto Rican endemic orchid;Ackerman;Lindleyana,1989
5. Seedling establishment in an epiphytic orchid: an experimental study of seed limitation;Ackerman;Oecologia,1996