I found a nice article on Passagemaker about bowlines that includes a link to a 59-page analysis of the
knot by Mark Gommers.
Mark Gommers is an Australian affiliated with that country’s Professional Association of Climbing Instructors. “An Analysis of the Structure of Bowlines,” which Gommers began researching in 2009, is wonderfully insightful in a goofy way and wonderfully illustrated. Reading it, you will learn that there are many variations on the bowline
concept. The report takes some deep dives on the subject.
See the link below.