Please follow http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&SID=7b8b0c3363d27c20bc73cea0a27a55b1&ty=HTML&h=L&n=49y2.1.1.3.7&r=PART#49:2.1.1.3.7.2.25.2.