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This contradicted the view associated with Niels Bohr and Werner Heisenberg , according to which a quantum particle does not have a definite value of a property like momentum until the measurement takes place .
 Niels Bohr, Werner Heisenberg
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Niels Bohr, Werner Heisenberg