APA

Blackstone E. G., Smith S. L., . (1949). Improvement of instruction in typewriting. New York: Prentice-Hall.

Chicago

Blackstone Earl Glen, Smith Sofronia Lucretia, . 1949. Improvement of instruction in typewriting. New York: Prentice-Hall.

Harvard

Blackstone E. G., Smith S. L., . (1949). Improvement of instruction in typewriting. New York: Prentice-Hall.

MLA

Blackstone Earl Glen, Smith Sofronia Lucretia, . Improvement of instruction in typewriting. New York: Prentice-Hall. 1949.