Gilbreth, R. D. (1987). Forward thinking: The pragmatist's guide to Today's Business Trends. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Gilbreth, Robert D. Forward Thinking: The Pragmatist's Guide to Today's Business Trends. New York: McGraw-Hill, 1987.
Lua MLA (9ú heag.)Gilbreth, Robert D. Forward Thinking: The Pragmatist's Guide to Today's Business Trends. McGraw-Hill, 1987.
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