المؤلفون: Cooper, Charlotte

Original Material: Edition: REV - Revised, 2

الإتاحة: https://www.jstor.org/stable/j.ctv36xvs22

المؤلفون: Stamford, Bryant A., Coffin, Becca

Original Material: 328 p.

الإتاحة: https://www.jstor.org/stable/j.ctt130j3sx

المؤلفون: STEARNS, PETER N.

Original Material: 294 p.

الإتاحة: https://www.jstor.org/stable/j.ctt9qg868