The United States of America (federal laws)
US Constitution (do I really need to list this one? See amendment 2...)
General firearms regulation. (This is a very hard read. Most of it deals with interstate transportation, sales, transfers, and manufacturing. However, sec 930 is possession on federal facilities. And possession on school grounds is buried in sec 922 it is a bit hard to find.)
A PDF download is available that you can print here.