5[8]Kronstrm M,Palmqvist S,Sderfeldt B,et al.Utilization of dental health services among middle-aged people in Sweden and Denmark[J].Acta Odontol Scand,2002,60 (5):276-280
6[9]Antoft P,Rambusch E,Antoft B,et al.Caries experience,dental health behaviour and social status--three comparative surveys among Danish military recruits in 1972,1982 and 1993[J].Community Dent Health,1999,16(2):80-84