17. Mandell RB. Basic principles of hydrogel lenses. In Mandell RB. Contact Lens Practice (4th ed.). Springfield, IL, Charles C. Thomas Publisher, 1988: 502-527.

17. Mandell RB. Basic principles of hydrogel lenses. In Mandell RB. Contact Lens Practice (4th ed.). Springfield, IL, Charles C. Thomas Publisher, 1988: 502-527.