1. Craig, R. A. and W. S. Hering,1959: The stratospheric warming of January-February 1957. J. Meteor., 16, 91-107.
2. Deland, R. J., 1965: Some observations of the behavior of spherical harmonic waves. Mon. Wea. Rev., 93, 307-312.
3. Free University of Berlin, 1967/68: Täglicher Höhenkarten der 100-mb-Fläche and der 50-mb-Fläche sowie monatliche Mittelkarten für das Jahr 1967. Teil IV. Meteor. Abhandl., Band LXXX, Heft 4.
4. Free University of Berlin, 1968a: Daily and monthly northern hemisphere 30-millibar-synoptic weather maps of the year 1967. Part IV. October-December. Meteor. Abhandl., Band LXXXI, Heft 4.
5. Free University of Berlin, 1968b: Daily and monthly northern hemisphere 10-millibar-synoptic weather maps of the year 1967. Part IV. October-December. Meteor. Abhandl., Band LXXXII, Heft 4.