191764
After working as a postdoctoral fellow with Hermann Rahn at Buffalo in 1961-62 , he returned to London as Director of the Respiratory Research Group at Postgraduate Medical School ( 1962-67 ) and was promoted to University Reader there in 1968 .
 Hermann Rahn, Buffalo
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Hermann Rahn, Buffalo