I meant scientific citation. This link doesn't contain any study. Moreover, it is from March, so quite beginning of pandemic.
So here you go:
- https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext
Here's nice article that mentions this meta-analysis of 172 studies, it's written in not scientific language and it's from 26th June 2020 - https://www.ucdavis.edu/coronavirus/news/your-mask-cuts-own-risk-65-percent/

Also, wearing such mask is about spreading virus to others. It's not only your mask that protects you to some extent, it's other people's masks that protects you and your mask protects others.