Williams, G. (1989). Change and approximation: Problem solving and projects related to course content. Gaye Williams Publications.
Lua i Stíl Chicago (17ú heag.)Williams, Gaye. Change and Approximation: Problem Solving and Projects Related to Course Content. Brighton, Vic: Gaye Williams Publications, 1989.
Lua MLA (9ú heag.)Williams, Gaye. Change and Approximation: Problem Solving and Projects Related to Course Content. Gaye Williams Publications, 1989.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.