On the discovery of Merceya ligulata in the Azores with a discussion of the so-called "copper mosses" - Persson, Herman 1893-1978 (Muséum National d'Histoire Naturelle, Laboratoire de Cryptogamie, 1948)
Extrait de la Revue Bryologique et Lichenologique. Tome 17, fascicule 1-4