1. CERN 63-55;Citron,1963
2. Conf. High energy cyclotron improvement;Telegdi,1964
3. Proc. Int. Symp. Magnet tech.;Foss,1965
4. Properties of an infinite focussing channel with successive quadrupole rotations not equal to 90°
5. W. M. Brobeck, Report 90-4-R20.