Sheller, W. D. (1991). Welcome to English: Work Book 4/ Willard D.Shelleer; Susan C.Bayley. Indonesia : English Language Services Inc..
Lua i Stíl Chicago (17ú heag.)Sheller, Willard D. Welcome to English: Work Book 4/ Willard D.Shelleer; Susan C.Bayley. Indonesia : English Language Services Inc., 1991.
Lua MLA (8ú heag.)Sheller, Willard D. Welcome to English: Work Book 4/ Willard D.Shelleer; Susan C.Bayley. Indonesia : English Language Services Inc., 1991.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.