1. Opgørelse over forekomst af produktionssygdomme i danske svinebesætninger;Christensen;Dansk Veterinærtidsskrift,1994
2. An integrated health and production surveillance system;Christensen,1992
3. Pig health and production surveillance in Denmark: sampling design, data recording, and measures of disease frequency;Christensen;Prev. Vet. Med.,1994
4. Incidence of clinical disease and slaughterhouse findings among fatteners in Danish swine herds;Christensen,1994
5. Validity of producer-recorded causes of preweaning mortality in the Danish Health and Production Surveillance System;Christensen,1992