Westheimer, D. (1974). The Olmec head. Joseph.
Lua i Stíl Chicago (17ú heag.)Westheimer, David. The Olmec Head. London: Joseph, 1974.
Lua MLA (8ú heag.)Westheimer, David. The Olmec Head. Joseph, 1974.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.