Question:
Which employer did Emil Leon Post work for in Apr, 1929?

Context:
 Emil Leon Post works for City College of New York from Jan, 1932 to Jan, 1954. 
 Emil Leon Post works for Princeton University from Jan, 1920 to Jan, 1921. 
 Emil Leon Post works for Columbia University from Jan, 1921 to Jan, 1924. 
 Emil Leon Post works for George Washington Educational Campus from Jan, 1927 to Jan, 1932. 
 Emil Leon Post works for Cornell University from Jan, 1924 to Jan, 1927.

Answer:
George Washington Educational Campus