Spencer, M. (1986). Contemporary economics (6th. ed.). Worth.
Lua i Stíl Chicago (17ú heag.)Spencer, Milton. Contemporary Economics. 6th. ed. New York: Worth, 1986.
Lua MLA (9ú heag.)Spencer, Milton. Contemporary Economics. 6th. ed. Worth, 1986.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.