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Polarization VLBI calibration at high frequencies has traditionally been difficult due to poor sensitivity and high antenna instrumental polarization across inhomogeneous networks. The higher observing frequency and increased spatial resolution diminishes the chances of finding ideal VLBI polarization calibrators. The advent of the Very Long Baseline Array (VLBA), which has standardized feeds with low instrumental polarization, has minimized these observational difficulties. Recent work in polarization calibration has suggested that somewhat resolved sources may be used in an iterative polarization calibration scheme (Cotton 1993). A full generalization of this method has been developed by Leppanen, Zensus and Diamond (1995) in calibrating 22 GHz polarization observations with the VLBA.