Brown, W. R. (1977). Earth science: A search for understanding: teacher's annotated edition. J.B. Lippincott.
Lua i Stíl Chicago (17ú heag.)Brown, Walter R. Earth Science: A Search for Understanding: Teacher's Annotated Edition. J.B. Lippincott, 1977.
Lua MLA (9ú heag.)Brown, Walter R. Earth Science: A Search for Understanding: Teacher's Annotated Edition. J.B. Lippincott, 1977.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.