Q. How can I find quality sources?

The term "quality sources" means different things in different disciplines, and for different projects within those disciplines.

The gold standards for "quality sources" are

1. A peer reviewed or refereed journal article
2. A chapter from a well-reviewed book (or the entire book) from an academic publisher, such as a university press.

For more information, see 

How can I find peer-reviewed or scholarly/refereed articles.

and

Book Reviews