Patents.
3,514,605; 3,535,992; 3,547,520; 3,549,254; 3,561,843; 3,561,863; 3,569,709; 3,627,404; 3,632,866; 3,650,602; 3,659,919; 3,663,095; 3,664,745; 3,675,018; 3,675,069; 3,675,153; 3,675,156; 3,677,651; 3,678,836; 3,678,831; 3,678,833; 3,679,928; 3,679,994; 3,679,995; 3,684,346; 3,684,352; 3,684,380; 3,684,979; 3,684,980; 3,684,381; 3,685,884; 3,686,940; 3,687,522; 3,687,523; 3,691,477; 3,691,482; 3,692,380; 3,692,381; 3,692,386; 3,692,997; 3,694,056; 3,694,057; 3,694,058; 3,695,743; 3,695,747; 3,695,750; 3,697,151; 3,697,153; 3,697,155; 3,698,793; 3,698,796; 3,699,374; 3,700,303; 3,700,306; 3,700,307; 3,700,310; 3,700,311; 3,700,312; 3,700,339; 3,701,579; 3,701,587; 3,701,588; 3,702,216; 3,702,218; 3,702,395.