1. Christensen RP, Christensen GJ. Service potential of all-ceramic fixed prostheses in areas of varying risk. Paper presented at: 21st Annual Meeting and Exhibition of the American Association for Dental Research; March 14, 1992; Boston.
2. Clinical aspects of unfilled and composite resins;Christensen,1982
3. Filled polymer crowns: 1–2 year status reports;Clin Res Associates Newsletter,1998