git-merge Documentation, Git Community, 2023 - The official manual page for the git merge command, describing its usage, options, and behavior.
Pro Git, Scott Chacon and Ben Straub, 2014 (Apress) - A comprehensive book on Git, with a dedicated section explaining basic branching and the merging process.
Git Merge Tutorial, Atlassian, 2023 - A clear and practical tutorial explaining how git merge works with illustrative diagrams and command examples.