Here are some Gartner white papers related to ECM/WCM. Unless covered by the umbrella ECM category, I have not specifically included Document Management topics in this list. You will need a Gartner subscription to read these papers.

Generic ECM/WCM

Title: Management Update: What You Should Know About Enterprise Content Management
Author(s): Mark Gilbert Debra Logan Karen Shegda Garth Landers Kenneth Chin
Last Revision Date: 24 Jul 2002
Summary:
Content management is a hot technology area for enabling efficient Web sites and workplaces. Gartner discusses how enterprises can sort through the content management puzzle and save money by buying only what they need.
http://www3.gartner.com/DisplayDocument?id=365057

Title: From Enterprise Content Management to SES and Beyond
Author(s): Mark Gilbert Lou Latham
Last Revision Date: 28 Feb 2003
Summary:
Enterprises are demanding flexible, content-based infrastructures for greater business productivity. The smart enterprise suite represents the natural evolution of content management, portals and collaboration.  
http://www3.gartner.com/DisplayDocument?id=387355

Title: Building a Web Content Management Request for Proposal
Author(s): Lou Latham Mark Gilbert Tom Berg
Last Revision Date: 27 Sep 2002
Summary:
This Strategic Analysis Report provides guidelines for enterprises seeking to construct a request for proposal for Web content management software and services.
http://www3.gartner.com/DisplayDocument?id=371869

Title: The 2002 Web Content Management Magic Quadrant
Author(s): Mark Gilbert Lou Latham
Last Revision Date: 06 Aug 2002
Summary:
The Gartner Web content management Magic Quadrant still has three leaders, but the number of vendors has shrunk in 2002. The remaining vendors are striving to differentiate themselves as WCM becomes more ubiquitous.
http://www3.gartner.com/DisplayDocument?id=365839

Title: Web Content Management Key Issues for 2003
Author(s): Mark Gilbert Lou Latham
Last Revision Date: 14 Feb 2003
Summary:
WCM has evolved considerably since 2000. Growth and turmoil in the market and underlying technologies have led the Key Issues for 2003 to focus on making the technology more ubiquitous through better integration and licensing.
http://www3.gartner.com/DisplayDocument?id=386056

Vendor-Specific

Title: Documentum 5 Content Management Software
Author(s): Karen Shegda
Last Revision Date: 12 Feb 2003
Summary:
Documentum 5 is a platform for building document and content management solutions. Documentum also markets a series of focused product packages–Editions–that are built on the Documentum 5 platform.  
http://www3.gartner.com/DisplayDocument?id=307407

Title: IBM Content Manager
Author(s): Karen Shegda
Last Revision Date: 05 Aug 2002
Summary:
An integrated document management product, IBM Content Manager lets organizations capture, store, manage and distribute all forms of digital content, including scanned paper documents and rich media.  
http://www3.gartner.com/DisplayDocument?id=308444