APA (7th ed.) Citation

Heller, B. (1994). The 100 most difficult business letters you'll ever have to write, fax, or e-mail : clear guidance on how to write your way out of the toughest busiess problems you will ever face / Bernard Heller: Clear guidance on how to write your way out of the toughest busiess problems you will ever face. HarperBusiness.

Chicago Style (17th ed.) Citation

Heller, Bernard. The 100 Most Difficult Business Letters You'll Ever Have to Write, Fax, or E-mail : Clear Guidance on How to Write Your Way Out of the Toughest Busiess Problems You Will Ever Face / Bernard Heller: Clear Guidance on How to Write Your Way Out of the Toughest Busiess Problems You Will Ever Face. New York, N.Y.: HarperBusiness, 1994.

MLA (9th ed.) Citation

Heller, Bernard. The 100 Most Difficult Business Letters You'll Ever Have to Write, Fax, or E-mail : Clear Guidance on How to Write Your Way Out of the Toughest Busiess Problems You Will Ever Face / Bernard Heller: Clear Guidance on How to Write Your Way Out of the Toughest Busiess Problems You Will Ever Face. HarperBusiness, 1994.

Warning: These citations may not always be 100% accurate.