Gretz, K. F. (1996). Professional selling: A consultative approach. Irwin.
芝加哥风格引文Gretz, Karl F. Professional Selling: A Consultative Approach. Chicago: Irwin, 1996.
MLA引文Gretz, Karl F. Professional Selling: A Consultative Approach. Irwin, 1996.
警告：这些引文格式不一定是100％准确.