Nygaard-Ostby, P., Edvardsen, S. and Spydevold, B.: Access to interproximal tooth surfaces by different bristle designs and stiffnesses of toothbrushes. J. Dent. Res., 87: 424-430, 1979.
Yankell, S. L. and Emling, R. C.: Comparative laboratory evaluation of two new toothbrushes regarding interproximal access efficacy. J. Clin Dent., 4: D1-D4, 1993.
Yost, K. G., Miluszewski, K. F. and Chen, A. C.: Laboratory evaluations of toothbrush interproximal penetration ratios. J. Clin Dent., 4: 125-127, 1994.
Volpenhein, D. W., Walsh, M. E., Dellerman, P. A. and Burkett, T. A.: A new method for in vitro evaluation of the interproximal penetration of manual toothbrushes. J. Clin Dent., 5: 27-33, 1994.
Grabenstetter, R. J., Broge, R. W., Jackson, F. L. and Radike, A. W.: The measurement of theabrasion of human teeth by dentifrice abrasives: A test utilizing radioactive teeth. J. D. Res., 37: 1060 -1068, 1958.