Patent Reviews: 4,480,896; 4,487,478; 4,492,436; 4,492,437; 4,496,222; 4,500,164; 4,500,778; 4,504,964; 4,511,220; 4,508,422; 4,508,431; 4,508,421; 4,512,639; 4,515,444; 4,516,832; 4,516,833; 4,516,839; 4,516,855; 4,516,856; 4,521,075