250918
He received a silver medal in the 6 metre class with the boat Elisabeth X at the 1952 Summer Olympics in Helsinki , together with Johan Ferner , Erik Heiberg , Finn Ferner and Carl Mortensen .
 Helsinki, Johan Ferner, Erik Heiberg, Finn Ferner, Carl Mortensen
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Helsinki, Johan Ferner, Erik Heiberg, Finn Ferner, Carl Mortensen