National Science Teachers Association & ebrary, Inc. (2001). Dig in!: Hands-on soil investigations. NSTA Press.
Chicagoスタイル(17版)引用形式National Science Teachers Association , Inc ebrary. Dig in!: Hands-on Soil Investigations. Arlington, Va.: NSTA Press, 2001.
MLA(9版)引用形式National Science Teachers Association , Inc ebrary. Dig in!: Hands-on Soil Investigations. NSTA Press, 2001.
警告: この引用は必ずしも正確ではありません.