Question:
Which employer did Abraham Fraenkel work for in Jan, 1957?

Context:
 Abraham Fraenkel works for University of Kiel from Jan, 1931 to Jan, 1933. 
 Abraham Fraenkel works for Bar-Ilan University from Jan, 1957 to Jan, 1957. 
 Abraham Fraenkel works for German Army from Jan, 1914 to Jan, 1918. 
 Abraham Fraenkel works for University of Marburg from Jan, 1918 to Jan, 1928. 
 Abraham Fraenkel works for Hebrew University of Jerusalem from Jan, 1933 to Jan, 1957.

Answer:
Bar-Ilan University