Leedy, P. Research planning and desing.
Lua i Stíl Chicago (17ú heag.)Leedy, Paul. Research Planning and Desing. [Lugar de publicación no identificado].
Lua MLA (9ú heag.)Leedy, Paul. Research Planning and Desing.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.