Referee Resources
Referee Scheduling (ArbiterSports): Here
2018:
U7 and U8 Referee Do's and Don'ts: Here
U7 and U8 Orientation: Here
U10 Orientation: Here
U12 and U14 Orientation: Here
Returning Referee Orientation: Here
2019:
New Referee Orientation: Here
Laws of the Game Changes for 2019-2020: Here
Summary of Laws of the Game Changes for 2019-2020: Here
Laws of the Game & other guidance
Because the links change frequently we have not reproduced them there. Search for USSF or FIFA Laws of the Game. AYSOTraining.org also has them. It requires you to log in with your eAYSO ID and last name.
Look for these titles:
Laws of the Game 2016-2017
Summary of Changes, 2016
Advice to Referees on the Laws of the Game
Guide to Procedures - has good information on signaling and mechanics for referees and assistant referees
Guidance for Referees and Coaches
USSF Position Papers
Other interesting links:
Ask the Ref - an unofficial community of officials, with Questions submitted and answers by a panel of experienced refs
Ask a Soccer Referee - another unofficial referee blog with useful Q&A and editorials
Sign up for AYSO Whistle Stop newsletter for officials: www.ayso.org/aboutayso/newsletters.htm