wolframalpha

https://www.wolframalpha.com

https://www.wolframalpha.com/input/?i=d%5E2%2Fdb%5E2+e%5E(-(x%2Fb)%5Ea)

JB statistics

https://www.jbstatistics.com

Hastie and Tibshirani - videos and books

https://www.r-bloggers.com/in-depth-introduction-to-machine-learning-in-15-hours-of-expert-videos

RoyalStatSoc

https://www.youtube.com/user/RoyalStatSoc/videos

stackexchange

https://stackexchange.com

https://math.stackexchange.com

https://stats.stackexchange.com

https://stackoverflow.com

https://tex.stackexchange.com