Sweeting, G. (1974). How to be a chalk artist (13ª ed.). Zondervan.
Cita Chicago (17th ed.)Sweeting, George. How to Be a Chalk Artist. 13ª ed. Zondervan, 1974.
Cita MLA (9th ed.)Sweeting, George. How to Be a Chalk Artist. 13ª ed. Zondervan, 1974.
Atenció: Aquestes cites poden no estar 100% correctes.