@unpublished{TUW-120844, author = {Mendes Cerveira, Pj. and Heinkelmann, Robert and Weber, Robert and Schuh, Harald}, title = {Associativity in the datum definition of VLBI analysis and its implication on the terrestrial reference frame}, year = {2007}, note = {poster presentation: EGU 2007, Wien; 2007-04-15 -- 2007-04-20} }