Collard, D. A. (1978). Altruism and economy: A study in non-selfish economics. Martin Robertson.
Lua i Stíl Chicago (17ú heag.)Collard, David A. Altruism and Economy: A Study in Non-selfish Economics. Oxford: Martin Robertson, 1978.
Lua MLA (9ú heag.)Collard, David A. Altruism and Economy: A Study in Non-selfish Economics. Martin Robertson, 1978.
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