Patents.
4,748,630; 4,762,400; 4,768,864; 4,775,218; 4,776,658; 4,778,251; 4,778,258; 4,787,077; 4,791,310; 4,779,001; 4,791,644; 4,792,208; 4,793,680; 4,795,226; 4,794,585; 4,794,605; 4,795,232; 4,795,901; 4,796,969; 4,801,183; 4,797,000; 4,801,184; 4,801,196; 4,801,202; 4,801,212; 4,802,183; 4,802,717; 4,801,798; 4,802,719; 4,802,748; 4,803,691; 4,805,623; 4,805,974; 4,805,997; 4,805,999; 4,806,003; 4,807,240; 4,807,950; 4,807,951; 4,807,970; 4,807,978; 4,807,990; 4,810,047; 4,810,069; 4,810,072; 4,810,074; 4,813,756;