Question:
Which employer did Barbara Keyfitz work for in Dec, 1977?

Context:
 Barbara Keyfitz works for Arizona State University from Jan, 1979 to Jan, 1983. 
 Barbara Keyfitz works for Columbia University from Jan, 1970 to Jan, 1976. 
 Barbara Keyfitz works for Princeton University from Jan, 1977 to Jan, 1979.

Answer:
Question:
Which employer did Barbara Keyfitz work for in Dec, 1977?

Context:
 Barbara Keyfitz works for Arizona State University from Jan, 1979 to Jan, 1983. 
 Barbara Keyfitz works for Columbia University from Jan, 1970 to Jan, 1976. 
 Barbara Keyfitz works for Princeton University from Jan, 1977 to Jan, 1979.

Answer:
user
Princeton University
assistant
Question:
Which employer did Barbara Keyfitz work for in Dec, 1977?

Context:
 Barbara Keyfitz works for Arizona State University from Jan, 1979 to Jan, 1983. 
 Barbara Keyfitz works for Columbia University from Jan, 1970 to Jan, 1976. 
 Barbara Keyfitz works for Princeton University from Jan, 1977 to Jan, 1979.

Answer:
user
Arizona State University
Columbia University
assistant
Question:
Which employer did Barbara Keyfitz work for in Dec, 1977?

Context:
 Barbara Keyfitz works for Arizona State University from Jan, 1979 to Jan, 1983. 
 Barbara Keyfitz works for Columbia University from Jan, 1970 to Jan, 1976. 
 Barbara Keyfitz works for Princeton University from Jan, 1977 to Jan, 1979.

Answer:
user
Princeton University
assistant