APA

Curtis H., . (1989). Biology. New York, N.Y: W. H. Freeman ; Worth Publishers.

Chicago

Curtis Helena, . 1989. Biology. New York, N.Y: W. H. Freeman ; Worth Publishers.

Harvard

Curtis H., . (1989). Biology. New York, N.Y: W. H. Freeman ; Worth Publishers.

MLA

Curtis Helena, . Biology. New York, N.Y: W. H. Freeman ; Worth Publishers. 1989.