Question:
Which employer did Djelal Kadir work for in May, 1994?

Context:
 Djelal Kadir works for Pennsylvania State University from Jan, 1997 to Jan, 1997. 
 Djelal Kadir works for University of Nevada, Reno from Jan, 1971 to Jan, 1973. 
 Djelal Kadir works for University of Oklahoma from Jan, 1991 to Jan, 1997. 
 Djelal Kadir works for Purdue University from Jan, 1973 to Jan, 1991.

Answer:
University of Oklahoma