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TWC Nos. 1 through 24 are licensed under the Creative Commons Attribution-Noncommercial 3.0 Unported License. For Nos. 1 through 24, TWC, not the author, retains copyright. For Nos. 25 forward, the author, not TWC, retains copyright under the Attribution 4.0 International (CC BY 4.0) License and may be freely reproduced.