Patents.
3,157,087; 3,215,777; 3,209,191; 3,361,548; 3,362,804; 3,313,204; 3,328,586; 3,269,258; 3,317,664; 3,326,080; 3,329,059; 3,330,951; 3,336,834; 3,344,280; 3,345,462; 3,347,133; 3,347,669; 3,358,557; 3,362,848; 3,370,172; 3,373,019; 3,374,358; 3,376,092; 3,377.910; 3,377,911; 3,378,326; 3,379,486; 3,379,530; 3,379,887; 3,383,460; 3,385,159; 3,386,786; 3,386,788; 3,388,629; 3,393,323; 3,393,372; 3,395,246; 3,395,960; 3,397,362; 3,398,277; 3,398,286; 3,398,665; 3,399,591; 3,398,632; 3,400,266; 3,400,274; 3,401,266; 3,401,268; 3,401,398; 3,401,399; 3,401,592; 3,401,593; 3,402,001; 3,402,295; 3,402,296; 3,402,977; 3,402,979; 3,402,980; 3,403,260; 3,403,261; 3,403,262; 3,404,353; 3,405,262; 3,405,614; 3,405,623; 3,405,992; 3,405,994; 3,406,252; 3,407,019; 3,407,296; 3,407,715; 3,408,134; 3,408,456; 3,408,497; 3,409,349; 3,409,354; 3,409,372; 3,409,373; 3,409,374; 3,409,777; 3,409,781; 3,410,623; 3,410,625; 3,410,627; 3,410,628; 3,410,629; 3,410,630; 3,410,631; 3,410,632; 3,410,633; 3,410,636; 3,410,644;