1. Sickness absence;Anonymous,1974
2. A study of certification in general practice;Grossmark, F.; Sharer, P.;Practitioner,1976
3. Sick absence certification: analysis of one practice in 1967;Carne, S.;BrMedJf
4. Certification of unfitness for work. JR Coll Gen Pract 1970; 19: 21 5-22;Lunn, J.; Rider, J.; Waters, W.; Charnock, R.;BRITISH MEDICAL JOURNAL VOLUME,1988
5. Sickness absence. I R Coll Gen Pract;Haines, A.,1982