| Year | 2013 |
| Date | 18-Oct |
| Volume | 211 |
| Issue | 4,467 |
| Page | 567 |
| Category | Postbag |
| Part | |
| Title | Patents worth pondering |
| Author | Andre Rousseau |
| Notes | Kasenit, pulse-jet engines, variable overhead valve mechanism, Husqvarna X-Torq 2-stroke engine, Stihl 2-mix, Tanaka 'Purefire', www.oldengine.org, Ossian Ringbom, see 209 4442 671 |