K3/EES 4/482-10  15.5.98
Database oriented DTD
Object oriented model
utree structure
uone to one and one to many relationships
uobjects grouped in container
uexpress relationship directly
uimplicit acess path to the data
umultiple relationships
ulinks of specific semantics
uoccurance operator
uallow various instances
matching one DTD
uuseful for subclassing
uInheritance
uby reference
uby position