Patents.
4,786,124; 4,798,466; 4,802,731; 4,802,733; 4,802,750; 4,802,755; 4,802,757; 4,803,686; 4,804,258; 4,804,264; 4,806,018; 4,806,778; 4,812,020; 4,815,800; 4,815,842; 4,824,191; 4,824,193; 4,826,290; 4,828,369; 4,828,372; 4,830,443; 4,831,269; 4,832,426; 4,832,447; 4,832,465; 4,832,472.