Cita APA (7a ed.)

(1970). Ecosystems: Teacher's guide (Trial ed.). Science Curriculum Improvement Study.

Cita Chicago Style (17a ed.)

Ecosystems: Teacher's Guide. Trial ed. Berkeley, CA: Science Curriculum Improvement Study, 1970.

Cita MLA (9a ed.)

Ecosystems: Teacher's Guide. Trial ed. Science Curriculum Improvement Study, 1970.