APA

Usher G., . (1970). A dictionary of botany. New York: Van Nostrand Reinhold.

Chicago

Usher George, . 1970. A dictionary of botany. New York: Van Nostrand Reinhold.

Harvard

Usher G., . (1970). A dictionary of botany. New York: Van Nostrand Reinhold.

MLA

Usher George, . A dictionary of botany. New York: Van Nostrand Reinhold. 1970.