Here's a phew my phellow philadelphian:
1. How To Succeed In Commercial Real Estate, by John L. Bowman
2. The Fundamentals of Listing and Selling Commercial Real Estate by Loren K. Keim
3. Negotiating Commercial Real Estate Leases by Martin I. Zankel
4. The Commercial Lease Guidebook: Learn How To Win The Leasing Game! by Thomas G. Mitchell
All are on Amazon.com, where you can read their reviews.
Also, here's a link to The Center For Commercial Real Estate:
http://www.centerforcommercialrealestate.com/index.html-El Luchador