1. A Blandin and Friede American Institution of Mechanical Engineers Conference KFKI preprint to be published in Phys Status Solidi KFKI preprint to te published Proc Low Temp Kyoto KFKI preprint SSP Status Van der Lugt;Kohn;Phys Radium Phys Rev Phys Rev Phys Rev B Phys LT Phys Solidi b Phys Rev Phys Rev Phys Chem Solids Phys Chem Solids Physica,1960