| U.S. Patent No. | Links |
| 3388385 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3388385.pn. |
| 3566160 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3566160.pn. |
| 3576983 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3576983.pn. |
| 3623156 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3623156.pn. |
| 3668461 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3668461.pn. |
| 3678466 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3678466.pn. |
| 3769621 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3769621.pn. |
| 3996562 | https://ppubs.uspto.gov/pubwebapp/external.html?q=3996562.pn. |
| 4059213 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4059213.pn. |
| 4070680 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4070680.pn. |
| 4078257 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4078257.pn. |
| 4091270 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4091270.pn. |
| 4106677 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4106677.pn. |
| 4198684 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4198684.pn. |
| 4300844 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4300844.pn. |
| 4309761 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4309761.pn. |
| 4327366 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4327366.pn. |
| 4381554 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4381554.pn. |
| 4611307 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4611307.pn. |
| 4774493 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4774493.pn. |
| 4834504 | https://ppubs.uspto.gov/pubwebapp/external.html?q=4834504.pn. |
| 5123102 | https://ppubs.uspto.gov/pubwebapp/external.html?q=5123102.pn. |
| 5128887 | https://ppubs.uspto.gov/pubwebapp/external.html?q=5128887.pn. |
| 5260886 | https://ppubs.uspto.gov/pubwebapp/external.html?q=5260886.pn. |
| 5530234 | https://ppubs.uspto.gov/pubwebapp/external.html?q=5530234.pn. |
| RE30743 | https://ppubs.uspto.gov/pubwebapp/external.html?q=RE30743.pn. |