2672
He resumed his studies only in 1902 when he wrote his PhD thesis in University of Greifswald .
 organization: PhD; organization: University of Greifswald
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:
 organization: PhD; organization: University of Greifswald