APA

Gray A., . (1890). A manual of the botany of the Northern United States. New York: .

Chicago

Gray Asa, . 1890. A manual of the botany of the Northern United States. New York: .

Harvard

Gray A., . (1890). A manual of the botany of the Northern United States. New York: .

MLA

Gray Asa, . A manual of the botany of the Northern United States. New York: . 1890.