4008
During the 1950 s he worked on introducing spectral theory into number theory , culminating in his development of the Selberg trace formula , the most famous and influential of his results .
 person: Selberg
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Selberg