Cita APA (7a ed.)

Lewis, N. (1985). Thirty days to the better english. Signet Book.

Cita Chicago Style (17a ed.)

Lewis, Norman. Thirty Days to the Better English. Estados Unidos: Signet Book, 1985.

Cita MLA (9a ed.)

Lewis, Norman. Thirty Days to the Better English. Signet Book, 1985.