Aqualung invention

The company: https://us.aqualung.com/pages/our-story

European regulators – historical review: http://www.vintagescubasupply.com/regseuro.html

Mechanism of scuba diving regulator in Wikipedia: https://en.wikipedia.org/wiki/Mechanism_of_diving_regulators

There is probably no more comprehensive source of knowledge than PADI Encyclopedia of Recreational Diving, chapter 3 from that source:

http://watersports.si/images/stories/docs/forms/dm/Ch3-Dive-equipment.pdf

https://www.leisurepro.com/blog/scuba-gear/how-a-scuba-diving-regulator-works/

US patent https://patentimages.storage.googleapis.com/46/cd/d3/100845bdf11b6a/US2485039.pdf

U2485039 patent by Émile Gagnan (1900 – 1984) and Jacques-Yves Cousteau (1910-1997). Gagnan worked earlier for liquid air company in France and Canada.

Z książki W oceanie życia Yves Paccaleta po polsku:

Aparat do nurkowania swobodnego. R7 Paccalet

US2485039