Question:
Which employer did Andrey V Chubukov work for in Feb, 1987?

Context:
 Andrey V Chubukov works for Institute for Physical Problems from Jan, 1985 to Jan, 1989. 
 Andrey V Chubukov works for Moscow State University from Jan, 1986 to Jan, 1989. 
 Andrey V Chubukov works for University of Wisconsin–Madison from Jan, 2000 to Jan, 2000. 
 Andrey V Chubukov works for University of Illinois system from Jan, 1990 to Jan, 1992. 
 Andrey V Chubukov works for Yale University from Jan, 1992 to Jan, 2000.

Answer:
Moscow State University