APA

Hekking W. H. A., Organization for Flora Neotropica (New York), . (1988). Violaceae. New York, New York, United States: The New York Botanical Garden.

Chicago

Hekking W H A, Organization for Flora Neotropica (New York), . 1988. Violaceae. New York, New York, United States: The New York Botanical Garden.

Harvard

Hekking W. H. A., Organization for Flora Neotropica (New York), . (1988). Violaceae. New York, New York, United States: The New York Botanical Garden.

MLA

Hekking W H A, Organization for Flora Neotropica (New York), . Violaceae. New York, New York, United States: The New York Botanical Garden. 1988.