| http://www.w3.org/ns/prov#value | - U.S. Pat. No. 4,152,508 discloses a silicone-containing hard contact lens material containing a first monomer having the formula (2): ##STR3## wherein R1 is hydrogen or methyl, a is an integer from 1-3, b and c are integers from 0-2, d is 0 or 1, A is methyl or phenyl, R2 is methyl or phenyl, and R3 and R4 represent either no group or methyl or phenyl groups; a second comonomer comprising an itaco
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