https://www.quora.com/profile/Treloar/Pressure-and-Vacuum-relief-vent-function-explained-with-an-example

https://articles.abilogic.com/submission-completed/584728/

https://medium.com/@treloar175/a-workhorse-in-the-marine-and-offshore-industry-the-pressure-vacuum-valve-pv-valve-5598459534b8

https://treloar-au.blogspot.com/2022/06/transferring-liquids-what-should-you.html