(Informatik-Spektrum: Vol. 27, No. 2, 2004) Donald Kossmann; Frank Leymann; Dirk Taubner
“A Web service is a software system
designed to support interoperable machine-tomachine interaction
over a network. It has an interface described in a
machine-processable format (specifically WSDL). Other systems
interact with the Web service in a manner prescribed by its
description using SOAPmessages, typically conveyed using HTTP
with an XML serialization in conjunction with other Web-related
standards.”H. Haas, A. Brown: Web Services
Glossary. W3C Working Draft, August 2003