Gregory, J., & Frey, C. (1977). Who's who in engineering (3rd ed.). New York: Engineers Joint Council.
Παραπομπή Chicago StyleGregory, Jean, and Carl Frey. Who's Who in Engineering. 3rd ed. New York: Engineers Joint Council, 1977.
Παραπομπή MLAGregory, Jean, and Carl Frey. Who's Who in Engineering. 3rd ed. New York: Engineers Joint Council, 1977.
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