Koba, S., & Mitchell, C. T. (2011). Hard-to-teach science concepts: A framework to support learners, grades 3-5. National Science Teachers Association.
Lua i Stíl Chicago (17ú heag.)Koba, Susan, agus Carol T. Mitchell. Hard-to-teach Science Concepts: A Framework to Support Learners, Grades 3-5. Arlington, Va.: National Science Teachers Association, 2011.
Lua MLA (9ú heag.)Koba, Susan, agus Carol T. Mitchell. Hard-to-teach Science Concepts: A Framework to Support Learners, Grades 3-5. National Science Teachers Association, 2011.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.