Toronto Mail Order Staff. (1990). "Questions Kids Ask About This and That (Questions Kids Ask, 27)". Grolier Limited.
Cita Chicago (17th ed.)Toronto Mail Order Staff. "Questions Kids Ask About This and That (Questions Kids Ask, 27)". Grolier Limited, 1990.
Cita MLA (9th ed.)Toronto Mail Order Staff. "Questions Kids Ask About This and That (Questions Kids Ask, 27)". Grolier Limited, 1990.
Atenció: Aquestes cites poden no estar 100% correctes.