Cowan, P. (1973). The future of planning. Sage Pub.
Lua i Stíl Chicago (17ú heag.)Cowan, Peter. The Future of Planning. Beverly Hills, Calif: Sage Pub, 1973.
Lua MLA (9ú heag.)Cowan, Peter. The Future of Planning. Sage Pub, 1973.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.