1. Bjerknes, J.: Exploration des perturbations atmosphériques à l'aide de sondages rapprochés dans le temps. Geofys. Publ.9, No. 9 (1932).
2. Palmén, E.: Aerologische Untersuchungen der atmosphärischen Störungen. Commentationes Physico-Mathematicae, Soc. Scient. Fennica7, No. 6 (1933).
3. Bjerknes, J., andE. Palmén: Investigations of Selected European Cyclones by Means of Serial Ascents. Geofys. Publ.12, No. 2 (1937).
4. Sawyer, J. S.: Day-to-Day Variations in the Tropopause. Geophys. Mem. No. 92, Vol.11, No. 7 (1954).
5. McClain, P., andE. F. Danielsen: Zonal Distribution of Baroclinity for Three Pacific Storms. J. Met.12, 314 (1955).