The Little Book of Trikes - Adam Quellin - Google Books

https://books.google.de/books?id=JFM853u12W4C&pg=PA55&dq=boom#v=onepage

Motor trikes have been around since the dawn of motoring, with many starting out as utility vehicles or prototypes of cars. But trikes haven’t died out or become mere relics of motoring history – companies all over the world still produce them today, and…