1. Periodontal disease awareness
2. 3. L Turtola, I. Rytomaa, H Murtomaa, S Helminen, and L. JauhiainenFollow-up study of the dental health care of Finnish university students(English summary). Kansanelakelaitoksen julkaisuja ML: 45. Helsinki1985 : 83 -91 .
3. 4. M. Rajala, Occurrence of tooth loss, dental caries and need of operative dental treatment in an industrial population . Publications of the University of Kuopio, Series Original Reports 2/1977, Kuopio1977 : 91 -5 .