លក់អោយមានគុណភាពជាមួយសៀវភៅ3ក្បាល

លក់អោយមានគុណភាពជាមួយសៀវភៅ3ក្បាល

1. The Challenger Sale by Matthew Dixon and Brent Adamson
2. SPIN Selling by Neil Rackham
3. How to Win Friends and Influence People by Dale Carnegie