APA

Maas P. J. M., Ruyters P., . (1986). Voyria and voyriella (Saprophytes gentianaceae). New York, New York, United States: Organization for Flora Neotropica.

Chicago

Maas Paul J M, Ruyters P, . 1986. Voyria and voyriella (Saprophytes gentianaceae). New York, New York, United States: Organization for Flora Neotropica.

Harvard

Maas P. J. M., Ruyters P., . (1986). Voyria and voyriella (Saprophytes gentianaceae). New York, New York, United States: Organization for Flora Neotropica.

MLA

Maas Paul J M, Ruyters P, . Voyria and voyriella (Saprophytes gentianaceae). New York, New York, United States: Organization for Flora Neotropica. 1986.