title: www-udk : a web-based environmental meta-information system. authors: rudolf legat , arne koschel , andree keitel , ralf kramer , claudia rolker , ralf nikolai , peter c. lockemann , konrad zirm. venue: sigmod record. year: 1997
title: environmental information systems. authors: oliver g &#252; nther. venue: acm sigmod record. year: 1997