6791
It has been suggested that oceanic overturn caused or contributed to the late Devonian and Permian–Triassic extinctions .
 Devonian, Permian–Triassic
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Devonian, Permian–Triassic