APA (7th ed.) Citation

Lawrence, W. F. (1991). DR DOS 6 by example. M & T. Books.

Chicago Style (17th ed.) Citation

Lawrence, William F. DR DOS 6 by Example. Redwood City, CA: M & T. Books, 1991.

MLA (8th ed.) Citation

Lawrence, William F. DR DOS 6 by Example. M & T. Books, 1991.