License
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- Attribution 4.0 (CC BY 4.0)53
- Attribution-NonCommercial 4.0 (CC BY-NC 4.0)12
- Attribution 3.0 United States11
- Attribution-NonCommercial-NoDerivs 3.0 United States8
- Attribution-NonCommercial-ShareAlike 4.0 (CC BY-NC-SA 4.0)6
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- CC0 1.0 Universal6
- Public Domain Mark 1.06
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- Apache 2.01
- Attribution-NoDerivatives 4.0 (CC BY-ND 4.0)1