Proctor, W. M. (1933). Vocations: The world's work and its workers (Rev. and enl. ed.). Houghton Mifflin Company.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रProctor, William Martin. Vocations: The World's Work and Its Workers. Rev. and enl. ed. Boston : New York [etc.]: Houghton Mifflin Company, 1933.
एमएलए (8वां संस्करण) प्रशस्ति पत्रProctor, William Martin. Vocations: The World's Work and Its Workers. Rev. and enl. ed. Houghton Mifflin Company, 1933.
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