Patents.
3,144,575; 3,350,566; 3,361,910; 3,368,076; 3,370,253; 3,371,215; 3,375,750; 3,378,687; 3,379,832; 3,381,127; 3,384,433; 3,387,163; 3,388,256; 3,389,256; 3,389,260; 3,389,267; 3,389,348; 3,389,950; 3,390,257; 3,390,274; 3,390,351; 3,390,605; 3,391,282; 3,391,969; 3,392,351; 3,393,320; 3,393,373; 3,393,601; 3,393,955; 3,394,003; 3,394,320; 3,395,364; 3,395,367; 3,397,025; 3,397,608; 3,396,344; 3,397,314; 3,398,272; 3,398,283; 3,398,287; 3,398,269; 3,398,379; 3,398,635; 3,399,014; 3,398,638; 3,399,016; 3,399,017; 3,399,592; 3,399,942; 3,399,993; 3,400,214; 3,400,275; 3,400,276; 3,400,994.