1. Allen, R. F. 1911. Studies in spermatogenesis and apogamy in ferns. Trans. Wis. Acad. Sci.17: 1–56.
2. Andersson-Kottö, I. 1931. The genetics of ferns. Bib. Genet.8: 269–294.
3. —. 1932. Observations on the inheritance of apospory and alternation of generations. Svensk. Bot. Tidskrift26: 99–106.
4. —. 1936. On the comparative development of alternating generations with special reference to ferns. Svensk. Bot. Tidskrift 30: 57–79.
5. —,And Gairdner, A. E. 1936. The inheritance of apospory inScolopendrium vulgare. Journ. Genet.32: 189–228.