Question:
Which employer did John R. Kirtley work for in Apr, 2018?

Context:
 John R. Kirtley works for Stanford University from Mar, 2006 to Dec, 2022. 
 John R. Kirtley works for IBM Thomas J. Watson Research Center from Feb, 1978 to Feb, 2006. 
 John R. Kirtley works for University of Pennsylvania from Sep, 1976 to Jan, 1978.

Answer:
Stanford University