OpenAI API Reference, OpenAI, 2024 - Provides official documentation for OpenAI's models, detailing API structure, authentication, and available model names.
Anthropic API Reference, Anthropic, 2024 - Offers official documentation for Anthropic's Claude models, including API usage and model parameters.
The Twelve-Factor App: III. Config, Adam Wiggins, 2011 - Explains the architectural principle of storing application configuration, such as API credentials, in environment variables.