Sources:
Patek Philippe
https://www.theguardian.com/lifeandstyle/2016/oct/19/luxury-watch-industry-survive-digital-age
https://www.watchcollectinglifestyle.com/house/history-of-patek-philippe
https://www.youtube.com/watch?v=TpFiiGkUdeg
https://www.patek.com/en/firm/historical past#1839-1877
https://www.patek.com/en/firm/about-time/the-gondolo-an-extraordinary-heritage
https://deployant.com/history-at-a-glance-the-story-of-patek-philippe/
The Stern household
https://www.lgt.com/en/magnet/entrepreneurship/patek-philippe-a-family-owned-company-that-has-existed-for-generations/#button2
https://www.forbes.com/websites/ricardogeromel/2014/04/15/time-is-money-for-luxury-watchmaker-patek-philippes-swiss-owner-and-now-billionaire-philippe-stern/?sh=7b50d4074d47