Fly Neighborly Guide published by the Helicopter Association International (HAI). (See Section 3 on Pages 7-9 for a discussion 65 dB criterion and suggested flying heights.)
Report by Noise Consultants Harris, Miller, Miller & Hanson (See Pages 46 & 50 - According to the acoustics industry, noise at 60 dB begins to interfere with outdoor speech communication.)
WebTrak (Online tracking system that allows you to view current and historical (back 3 months) aircraft flight tracks and altitudes in the Los Angeles area, including Torrance.) To view on AOL use: http://ems02.bksv.com/webtrak/lax4 .
FAA Website (To look up N-Numbers and identify aircraft type and registered owner.)