Question:
Which employer did Wilfrid Sellars work for in May, 1983?

Context:
 Wilfrid Sellars works for Yale University from Jan, 1958 to Jan, 1963. 
 Wilfrid Sellars works for University of Iowa from Jan, 1938 to Jan, 1946. 
 Wilfrid Sellars works for University of Pittsburgh from Jan, 1963 to Jan, 1989. 
 Wilfrid Sellars works for University of Minnesota from Jan, 1947 to Jan, 1958.

Answer:
University of Pittsburgh