Walter I. Wittmann: The Sea Ice Forecasting Program.
The Institute of Navigation, Washington, D. C.
Hilsen fra Walt Wittmann på tittelblad.
Reprintet from Navigation, Journal of the Institute of Navigation, Vol. 8, No. 4, Winter 1961-1962. 8vo. 267-272 s. Orig. omslag.
Stor foldeplansje.