Association, N. S. T. (1969). How to do it series. NSTA.
Cita Chicago (17th ed.)Association, National Science Teachers. How to Do It Series. Washington, D.C: NSTA, 1969.
Cita MLA (9th ed.)Association, National Science Teachers. How to Do It Series. NSTA, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.