1. Chapter inMethods and Techniques in Geophysics, edited by S. K. Runcorn, Interscience Publishers, 1960.
2. (Mk I) p. 343, 344, andTrans. I. À. U. vol. VIII, p. 268 to 271, 1952.
3. Orlov, A. I.Service des Latitudes, p. 92, Moscow, 1958.
4. Chapter 8 inStars and Stellar Systems, vol. I , edited by G. Kuiper and B. Middlehurst. (In press) .