An Introduction to Statistical Learning with Applications in R, Gareth James, Daniela Witten, Trevor Hastie, Rob Tibshirani, 2021 (Springer) - A foundational textbook that explains the statistical reasons behind data splitting for model assessment and selection.
Applied Predictive Modeling, Max Kuhn and Kjell Johnson, 2013 (Springer)DOI: 10.1007/978-1-4614-6849-3 - Discusses various data splitting strategies, including considerations for dataset size and the importance of representative sets, from an applied perspective.