Environment variables in Compose, Docker, 2024 (Docker, Inc.) - The official documentation provides comprehensive guidance on defining, substituting, and managing environment variables within Docker Compose, including .env files and precedence rules.
Docker in Action, Third Edition, Jeff Nickoloff, Stephen Kuenzli, 2019 (Manning Publications) - This book offers an exploration of Docker and Docker Compose, with dedicated sections on service configuration and best practices for managing environment variables in multi-container setups.