Havighurst, R. J. (1972). Development tasks and education (3rd ed.). David McKay Company, Inc..
Lua i Stíl Chicago (17ú heag.)Havighurst, Robert James. Development Tasks and Education. 3rd ed. New york: David McKay Company, Inc., 1972.
Lua MLA (8ú heag.)Havighurst, Robert James. Development Tasks and Education. 3rd ed. David McKay Company, Inc., 1972.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.