1. https://en.wikipedia.org/wiki/Patina
2. https://www.adamsbronze.com/bronze-patinas/
3. https://www.sciencedirect.com/topics/materials-science/patin...
3a. https://www.sciencedirect.com/science/article/abs/pii/S23524...
4. https://www.corrosionpedia.com/important-facts-you-might-not...
5. https://www.accurateimageinc.com/CutMetals/Finish_CutBrnzPat...