Charters, W. W., Betz, A., & Cowan, E. M. (1930). Essential language habits. Silver, Burdett and Company.
Lua i Stíl Chicago (17ú heag.)Charters, W. W., Annette Betz, agus Esther Marshall Cowan. Essential Language Habits. New York, Chicago [etc.]: Silver, Burdett and Company, 1930.
Lua MLA (8ú heag.)Charters, W. W., et al. Essential Language Habits. Silver, Burdett and Company, 1930.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.