1. BMDP statistical software manual;BMDP, Inc.,1988
2. Provisional estimates for July 1, 1989 and revised estimates for 1986, 1987 and 1988;California Department of Finance,1990
3. Driver licensing information, county, age, and sex;California Department of Motor Vehicles,1980
4. Age and sex report;California Department of Motor Vehicles,1989
5. 1979–1989 annual report of fatal and injury motor vehicle traffic accidents (10 volumes);California Highway Patrol,1980