Abstract
The eXtensible Markup Language (XML) is well accepted in many different application areas. As a consequence, there is an increasing need for storing XML documents persistently. As soon as many users and applications work concurrently on the same collection of XML documents - i.e. an XML base - isolating accesses and modifications of different transactions becomes an important issue. We discuss two different timestamp-based protocols for synchronizing access on XML document collections. These core protocols synchronize structure traversals and modifications. Further, we extend the protocols to handle node contents and IDREF jumps, so that they can be integrated into a native XML base management System (XBMS)