Citation: Lj. Llewellyn et al., USE OF SEQUENTIAL CASE-CONTROL STUDIES TO INVESTIGATE A COMMUNITY SALMONELLA OUTBREAK IN WALES, Journal of epidemiology and community health, 52(4), 1998, pp. 272-276
Citation: Lj. Llewellyn et I. Harvey, HEPATITIS-B VACCINATION - HOW MANY DOCTORS ARE FULLY COVERED, Journal of public health medicine, 16(3), 1994, pp. 352-356