1878. Vergleichende Anatomie der Samen von Vicia und Ervum. In Sitzber. K. Akad. Wiss. [Vienna], Math. Naturw. Kl., Bd. 77, Abt. 1, p. 545-579, 2 pl.
([2]) Bergtheil, C, and Day, D. L.
1907. On the cause of "hardness" in the seeds of Indigofera arrecta. In Ann. Bot., v. 21, no. 81, p. 57-60, pl. 7.
([3]) Crocker, William.
1906. Role of seed coats in delayed germination. In Bot. Gaz., v. 42, no. 4, p. 265-291, 4 fig. Literature cited, p. 290-291.
([4]) Darwin, Charles.
1885. The effects of cross and self fertilisation in the vegetable kingdom. 482 p. New York.
([5]) Ewart, Alfred J.
1908. On the longevity of seeds. In Proc. Roy. Soc. Victoria, v. 21, pt. 1, p. 1-203. Literature, p. 3-4.
([6]) Gola, Guiseppe.