Peter Baumann Valences: A new Relationship Concept for the Entity-Relationship Model. 59-72 1989 ER db/conf/er/er89.html#Baumann89 conf/er/89 er89/ER89-P059.pdf db/conf/er/Baumann89.html conf/er/AtzeniC83 journals/tods/AbiteboulH87 conf/scm/BaumannK88 ... conf/er/Brodie81 journals/tods/Chen76 conf/er/83 conf/ifip/DittrichGL86 journals/dke/ElmasriWH85 ... ... conf/vldb/HarderMMS87 journals/csur/HullK87 conf/vldb/JunetFL86 ... conf/er/LenzeriniS83 books/mit/shriverW87/MaierS87 conf/wi/NeumannCGS87 conf/ds/ParentS85 ... ... conf/er/UrsprungZ83