Here's the quote you seek. Oskar Lange, "On the Economic Theory of   
Socialism," reprinted in _On the Economic Theory of Socialism_, edited by   
Benjamin E. Lippincott  (U. Minnesota Press, 1938), pp. 57-58: "Both as an   
expression of recognition for the great service rendered by him and as a   
memento of the prime importance of sound economic accounting, a statue of   
Professor Mises ought to occupy an honorable place in the great hall of   
the Ministry of Socialization or of the Central Planning Board of the   
socialist state."   
  
Bruce Caldwell