Am using the algorithm described here (https://stackoverflow.com/questions/21622956/how-to-convert-direction-vector-to-euler-angles) in the first answer for a thesis in software development. I do require a source to reference the mathematical background though because stackoverflow is hardly a scientific source unfortunately. Does this procedure have a name or does it appear in a book or how could I reference it?
Hope someone has a suggestion. Huge thanks in advance :)