Question:
Which employer did Sergio Villalobos work for in Oct, 1991?

Context:
 Sergio Villalobos works for University Finis Terrae from Jan, 2000 to Jan, 2001. 
 Sergio Villalobos works for Bernardo O'Higgins University from Jan, 2011 to Jan, 2015. 
 Sergio Villalobos works for University of Cambridge from Jan, 1991 to Jan, 1992. 
 Sergio Villalobos works for Pontifical Catholic University of Chile from Jan, 1970 to Jan, 2003. 
 Sergio Villalobos works for University of Chile from Jan, 1951 to Jan, 1951. 
 Sergio Villalobos works for San Sebastián University from Jan, 2016 to Dec, 2022. 
 Sergio Villalobos works for Andrés Bello University from Jan, 2002 to Jan, 2010.

Answer:
University of Cambridge