1. Abbe, E. C. 1974. Flowers and inflorescences of the “Amentiferae.” Bot. Rev.40(2): 159–261.
2. Agababian, V. Sh. 1961. Materials on the palynosystematic study of the family Saxifragaceae s.l. Izv. Armenian Acad. Sci., Biol. Sci.14(2): 45–61. (In Russian).
3. —. 1964. Evolution of pollen grains in the orders Cunoniales and Saxifragales in relation to some problems in their systematics and phylogeny. Izv. Armenian Acad. Sci., Biol. Sci.17: 59–72. (In Russian).
4. -. 1973. Pollen grains of primitive angiosperms. (In Russian). Erevan.
5. Agarwal, S. 1963. Morphological and embryological studies in the family Olacaceae. I.Olax L. Phytomorphology13: 185–196.