APA
Gerber P. L., . (1975). Willa Cather. Boston: Twayne Publishers.
Chicago
Gerber Philip L, . 1975. Willa Cather. Boston: Twayne Publishers.
Harvard
Gerber P. L., . (1975). Willa Cather. Boston: Twayne Publishers.
MLA
Gerber Philip L, . Willa Cather. Boston: Twayne Publishers. 1975.