Office rentals.(Operations: CardFile)(Directory)

* LoopNet (www.loopnet.com)--Nationwide database of commercial real estate listings; directory of brokers.

* Sublease.com (www.sublease.com)--Nationwide database of available subleases.

* PikeNet (www.pikenet.com)--Extensive listings of real estate services & products.

* TenantWise (www.tenantwise.com)--Insightful articles about lease negotiations.

* Leasing Professional (www.leasingprofessional.com)--Comprehensive collection of lease templates, clauses, reference guides; $24.95+ each.

* Robert Thomas Group (www.rentaudit.com)--Audit service to find cost savings in commercial leases.

* Reis (www.reis.com)--Economic data on local rents, vacancy rates, etc.

* Negotiating Commercial Real Estate Leases, by Martin Zankel--Practical business strategies for dealing with landlords; $19.95.