1. C. D. Michener. Revista de Biologia Tropical. 10, 167–175 (1962).
2. S. L. Buchmann, Handbook of experimental pollination biology (Van Nostrand; New York, USA, 1983), pp 73–113.
3. Extrafloral Nectaries in Solanum
4. A. Wille. Revista de Biologia Tropical. Letters 27, 241–277 (1963).
5. A biophysical model for buzz pollination in angiosperms