Patents.
3,196,743; 3,201,587; 3,269,253; 3,420,600; 3,421,815; 3,218,916; 3,302,028; 3,422,269; 3,423,146; 3,423,155; 3,427,091; 3,428,388; 3,428,397; 3,431,052; 3,433,141; 3,435,209; 3,435,744; 3,437,410; 3,438,316; 3,440,419; 3,442,193; 3,442,568; 3,443,856; 3,445,156; 3,449,581; 3,442,571; 3,449,587; 3,453,386; 3,454,343; 3,451,740; 3,454,758; 3,454,769; 3,455,223; 3,455,628; 3,457,407; 3,457,407; 3,457,416; 3,459,945; 3,460,884; 3,461,290; 3,464,763; 3,464,764; 3,465,155; 3,466,111; 3,466,113; 3,466,114; 3,466,115; 3,466,116; 3,466,117; 3,466,118; 3,466,120; 3,467,462; 3,467,464; 3,467,774; 3,467,775; 3,467,829; 3,467,906; 3,469,098; 3,469,107; 3,469,900; 3,469,925; 3,470,310; 3,470,372; 3,471,213; 3,471,217; 3,471,218; 3,471,219; 3,471,236; 3,471,698; 3,471,863; 3,472,574; 3,472,576; 3,472,577; 3,472,578; 3,472,596; 3,472,598; 3,473,027;