Patents.
3,674,336; 3,674,339; 3,674,341; 3,674,342; 3,675,151; 3,675,152; 3,675,553; 3,675,990; 3,677,616; 3,677,617; 3,677,653; 3,678,410; 3,679,286; 3,679,290; 3,679,291; 3,679,292; 3,679,293; 3,679,899; 3,679,299; 3,679,996; 3,679,997; 3,680,943; 3,680,945; 3,680,950; 3,680,961; 3,680,963; 3,681,606; 3,681,709; 3,681,519; 3,681,710; 3,682,526; 3,682,527; 3,682,529; 3,682,530; 3,682,533; 3,682,534; 3,682,536; 3,682,638.