Greer, P., & Lafferty, G. (2015). 40/40 vision: Clarifying your mission in midlife. IVP Books.
Lua i Stíl Chicago (17ú heag.)Greer, Peter, agus Greg Lafferty. 40/40 Vision: Clarifying Your Mission in Midlife. Downers Grove, IL: IVP Books, 2015.
Lua MLA (9ú heag.)Greer, Peter, agus Greg Lafferty. 40/40 Vision: Clarifying Your Mission in Midlife. IVP Books, 2015.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.