References for Alexander Friedmann

1. A T Grigorian, Biography in Dictionary of Scientific Biography (New York 1970-1990).
   http://www.encyclopedia.com/doc/1G2-2830901530.html
2. Biography in Encyclopaedia Britannica.
   http://www.britannica.com/eb/article-9035428/Aleksandr-Aleksandrovich-Friedmann

Books:

3. E A Tropp, V Ya Frenkel and A D Chernin, Alexander A. Friedmann : the man who made the universe expand (Cambridge, 1993).

Articles:

4. A F Gavrilov, In memory of A A Friedmann, Uspekhi fizicheskikh nauk 6 (1926), 73-75.

December 1997