APA

Gertsch W. J., . (1979). American spiders. New York: Van Nostrand Reinhold.

Chicago

Gertsch Willis J, . 1979. American spiders. New York: Van Nostrand Reinhold.

Harvard

Gertsch W. J., . (1979). American spiders. New York: Van Nostrand Reinhold.

MLA

Gertsch Willis J, . American spiders. New York: Van Nostrand Reinhold. 1979.