When conducting research, the following sources are generally considered reliable:
- Online textbook: These are often vetted and credible academic sources.
- The National Archives: This is a reputable institution that provides access to primary historical documents and records, making it a reliable source.
On the other hand:
- Wikipedia: While it can be a good starting point for research and provides useful overviews, it's not considered a reliable source on its own because the content can be edited by anyone.
- A blog or personal site: These typically represent personal opinions or experiences and are not generally considered reliable unless authored by an expert in the field and properly cited.
So, the reliable sources from your list are:
- Online textbook
- The National Archives