Received his Ph. D. in 1960 .
Igor Yakovlevich Birman ( July 25 , 1928 -- April 6 , 2011 ) was a Russian - American economist .
Received Igor Yakovlevich Birman 's Ph. D. in 1960 .
Igor Yakovlevich Birman ( July 25 , 1928 -- April 6 , 2011 ) was a Russian - American economist .