Isard, W. (1975). Introduction to regional science. Prentice-Hall.
Lua i Stíl Chicago (17ú heag.)Isard, Walter. Introduction to Regional Science. .Englewood Cliffs, N.J: Prentice-Hall, 1975.
Lua MLA (9ú heag.)Isard, Walter. Introduction to Regional Science. Prentice-Hall, 1975.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.