The quick short answer is FAI Sporting Code Section 3 paragraph: 3.1.4

If you are serious about this, visit http://www.fai.org/gliding/ and
download the Sporting Code ( http://www.fai.org/sporting_code/sc3.asp
).

You should also get the
General Section: (
http://www.fai.org/documents/sportin...ction_download ) and

Official Observers Guide: ( http://www.fai.org/sporting_code/sc3c.pdf
)

SAA State Records: (
http://www.ssa.org/members/badgesandrecords/forms.asp )