https://www.reddit.com/r/typewriters/comments/1kbhf3a/older_man_clearing_storage_area_gave_me_seven/

https://www.r-m.de/en-us/bikes/

https://www.scientificamerican.com/article/bicycle-technology/

This is the article Steve Jobs is referencing in his bicycle for the mind quote.

Wilson, S. S. “Bicycle Technology.” Scientific American 228, no. 3 (1973): 81–91. https://doi.org/10.1038/scientificamerican0373-81