Patents.
4,685,780; 4,689,809; 4,690,550; 4,701,035; 4,703,434; 4,705,357; 4,708,425; 4,708,479; 4,709,146; 4,709,580; 4,711,575; 4,712,912; 4,712,917; 4,713,533; 4,713,818; 4,715,683; 4,715,713; 4,718,056; 4,718,754; 4,719,354; 4,720,171; 4,720,172; 4,720,193; 4,720,637; 4,721,352; 4,723,845; 4,728,194; 4,729,620; 4,732,447; 4,733,938; 4,737,001; 4,737,003; 4,737,007; 4,737,621; 4,737,973; 4,738,496; 4,738,498; 4,738,517; 4,738,518; 4,741,606; 4,743,093; 4,743,094; 4,743,097; 4,743,100; 4,743,101; 4,743,102; 4,743,103; 4,743,113; 4,743,114; 4,743,758; 4,744,616; 4,744,618; 4,744,625; 4,744,636; 4,745,591; 4,746,182; 4,746,186; 4,746,191; 4,746,204; 4,746,205; 4,747,646; 4,747,647; 4,747,665; 4,748,680.