Website of the lab that made DeepLabCut:
http://www.mackenziemathislab.org/deeplabcut
Papers to read if you want to learn more about DLC:
Mathis et al (2018): https://www.nature.com/articles/s41593-018-0209-y
Mathis et al (2019) : https://www.nature.com/articles/s41596-019-0176-0