For Further Research

For any of you who had interests, see below for further resources.

1. For those who want to know "solid" academics.
Google Sholar is a very wide browser to search for an academic paper, book and experiment results. The same for this topic, you can customize some search criteria to find out what you want to know further. The contents are very academic for must.
https://scholar.google.com/

2. For those who want to learn more, without reading hardcore books.
NewYorkTimes is a fit for those who are willing to know, but casually. You can search for "media bias" in the search form and find articles about specifics. The reliability can be a little bit low, so I recommend to use Google Sholar at the same time for any doubt.
https://www.nytimes.com/

3.For those who seek for the industry-focused case.
If you have happened to be interested to know about bias in the USA, the website by the American Press Institute will be the exact spot. The number of contents is not huge, but the analysis by the industry leader is very reliable and interesting with good readability.

https://www.americanpressinstitute.org/