%0 Patent %D 1993 %T Zirconia Toughening of Glass-Ceramic Materials %A Adams, Richard W. Jr. %A David R. Clarke %A Sarah H. Knickerbocker %A Linda L. Rapp %A Bernard Schwartz %7 United States of America %V 5185215 %G eng %U files/clarke/files/us5185215.pdf %& US