License
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- CC0 1.0 Universal23
- Public Domain Mark 1.014
- Attribution-NonCommercial-NoDerivs 3.0 United States11
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- Attribution-NonCommercial-NoDerivatives 4.0 (CC BY-NC-ND 4.0)4
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- Attribution-NoDerivatives 4.0 (CC BY-ND 4.0)2
- Attribution-ShareAlike 3.0 United States2
- Attribution-NonCommercial 3.0 United States1