Citação norma APA

(1994). Project learning tree: Environmental education activity guide (2nd.). Project Learning Tree.

Citação norma Chicago

Project Learning Tree: Environmental Education Activity Guide. 2nd. Washington: Project Learning Tree, 1994.

Citação norma MLA

Project Learning Tree: Environmental Education Activity Guide. 2nd. Project Learning Tree, 1994.

Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.