This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Five color theorem. Five color theorem own transferred from org el transferred to Commons by User MARKELLOS using de php CommonsHelper PDAUTHOR original upload log page el Grafio bytes no Graph coloring Mathematical theorems
Page 2023 Free-images.com. All images are Public Domain