69704
Several other promethium isotopes such as Pm , Pm , and Pm also have a positive energy release for alpha decay ; their alpha decays are predicted to occur but have not been observed .
 Pm, Pm, Pm
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Pm, Pm, Pm