APA-ийн эшлэл(7 дахь хэвлэлт)

Koba, S., & Mitchell, C. T. (2011). Hard-to-teach science concepts: A framework to support learners, grades 3-5. National Science Teachers Association.

Чикаго-гийн эшлэл (17 дахь хэвлэлт)

Koba, Susan, ба Carol T. Mitchell. Hard-to-teach Science Concepts: A Framework to Support Learners, Grades 3-5. Arlington, Va.: National Science Teachers Association, 2011.

MLA -ийн эшлэл (9 дэх хэвлэлт)

Koba, Susan, ба Carol T. Mitchell. Hard-to-teach Science Concepts: A Framework to Support Learners, Grades 3-5. National Science Teachers Association, 2011.