Watson, E.-V. — British Mosses and Liverworts. An introductory work, with full descriptions and figures of over 200 species, and keys for the identification of all except the very rare species. Second edition. Cambridge, University Press, 1968

Bourlière François. Watson, E.-V. — British Mosses and Liverworts. An introductory work, with full descriptions and figures of over 200 species, and keys for the identification of all except the very rare species. Second edition. Cambridge, University Press, 1968. In: La Terre et La Vie, Revue d'Histoire naturelle, tome 23, n°2, 1969. p. 222