Patents.
4,659,185; 4,688,881; 4,690,500; 4,693,547; 4,693,549; 4,693,569; 4,699,452; 4,699,464; 4,699,465; 4,701,005; 4,701,006; 4,701,009; 4,701,031; 4,701,033; 4,701,034; 4,702,245; 4,702,547; 4,702,548; 4,703,993; 4,703,994 ; 4,703,996; 4,705,345; 4,705,351; 4,705,354; 4,705,356; 4,705,362; 4,705,363; 4,705,364; 4,707,054; 4,707,055; 4,707,063; 4,707,077; 4,707,081; 4,707,082; 4,707,084; 4,707,085; 4,707,098; 4,707,611; 4,711,533; 4,711,534; 4,711,535; 4,711,536.