Bootstrap tutorial - for good web page designing

Question

To improve my web designing skill, I started learning Bootstrap. Apart from w3school, if you have some good tutorial, please provide me.

Answer 1

http://getbootstrap.com/docs/4.1/getting-started/introduction/
http://www.tutorialspoint.com/bootstrap/index.htm
https://www.sololearn.com/learn/1051/?ref=app