National Science Teachers Association & ebrary, Inc. (2001). Dig in!: Hands-on soil investigations. NSTA Press.
Chicago-čujuhus (17. p.)National Science Teachers Association juo Inc ebrary. Dig in!: Hands-on Soil Investigations. Arlington, Va.: NSTA Press, 2001.
MLA-čujuhus (9. p.)National Science Teachers Association juo Inc ebrary. Dig in!: Hands-on Soil Investigations. NSTA Press, 2001.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.