National Science Teachers Association & ebrary, Inc. (2001). Dig in!: Hands-on soil investigations. NSTA Press.
Cita Chicago Style (17a ed.)National Science Teachers Association y Inc ebrary. Dig in!: Hands-on Soil Investigations. Arlington, Va.: NSTA Press, 2001.
Cita MLA (9a ed.)National Science Teachers Association y Inc ebrary. Dig in!: Hands-on Soil Investigations. NSTA Press, 2001.
Precaución: Estas citas no son 100% exactas.