Ruskin, R. S. (1974). The personalized system of instruction: An educational alternative. Americam Association for Higher Education.
Lua i Stíl Chicago (17ú heag.)Ruskin, Robert S. The Personalized System of Instruction: An Educational Alternative. Washington, D.C.: Americam Association for Higher Education, 1974.
Lua MLA (9ú heag.)Ruskin, Robert S. The Personalized System of Instruction: An Educational Alternative. Americam Association for Higher Education, 1974.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.