Hiebeler, R. (1998). Best Practices Building Your Business With Customer-focused Solutions Robert Hiebeler, Thomas B. Kelly, Charles Ketteman. Simon & Schuster.
Lua i Stíl Chicago (17ú heag.)Hiebeler, Robert. Best Practices Building Your Business With Customer-focused Solutions Robert Hiebeler, Thomas B. Kelly, Charles Ketteman. Simon & Schuster, 1998.
Lua MLA (8ú heag.)Hiebeler, Robert. Best Practices Building Your Business With Customer-focused Solutions Robert Hiebeler, Thomas B. Kelly, Charles Ketteman. Simon & Schuster, 1998.
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