93893
In 1992 , the idea of creative destruction was put into formal mathematical terms by Philippe Aghion and Peter Howitt , giving an alternative model of endogenous growth compared to Paul Romer 's expanding varieties model .
 person: Philippe Aghion; person: Peter Howitt; person: Paul Romer
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: Philippe Aghion, Peter Howitt, Paul Romer 
Answer:
 person: Philippe Aghion; person: Peter Howitt; person: Paul Romer