Sund, R. B., Tillery, B. W., & Trowbridge, L. W. (1970). Elementary science discovery lessons. Allyn and Bacon.
Lua i Stíl Chicago (17ú heag.)Sund, Robert B., Bill W. Tillery, agus Leslie W. Trowbridge. Elementary Science Discovery Lessons. Boston: Allyn and Bacon, 1970.
Lua MLA (8ú heag.)Sund, Robert B., et al. Elementary Science Discovery Lessons. Allyn and Bacon, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.