Here are some documents that describe K2:
The Information Integration System
K2
A white paper by Val Tannen which describes how K2 tackles the problem of
information integration.
K2/Kleisli
and GUS: Experiments in Integrated Access to Genomic Data
Sources
A comparison of K2 with GUS, a data warehouse also developed at Penn.
Also available in Postscript
format.
K2 and Information
Integration
Jonathan Crabtree's description of the K2 approach to
information integration, particularly integration of semistructured
data.