WESPA rules for tournament Scrabble https://www.wespa.org/wesparulesv4.pdf
NASPA rules https://www.scrabbleplayers.org/rules/rules-20161201.pdf
Hasbro / Mattel Standard Rules can be found in Appendix 1 of the WESPA rules, These are the rules you would most likely find in your Scrabble board.
Mack Meller How to Get Better at Scrabble Without Memorizing Tons of Words Part 1: Rules and Overview
The Rules of Scrabble by Kenji Matsumoto