APA

Grabau A. W., . (1931). The permian of Mongolia. New York: The Am.Museum of Natural History.

Chicago

Grabau Amadeus W, . 1931. The permian of Mongolia. New York: The Am.Museum of Natural History.

Harvard

Grabau A. W., . (1931). The permian of Mongolia. New York: The Am.Museum of Natural History.

MLA

Grabau Amadeus W, . The permian of Mongolia. New York: The Am.Museum of Natural History. 1931.