Gifford, E. W., & Gifford, D. S. (1960). Archaeological excavations in Yap. University of California Press.
Lua i Stíl Chicago (17ú heag.)Gifford, Edward Winslow, agus Delila S. Gifford. Archaeological Excavations in Yap. [Berkeley: University of California Press, 1960.
Lua MLA (9ú heag.)Gifford, Edward Winslow, agus Delila S. Gifford. Archaeological Excavations in Yap. University of California Press, 1960.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.