There are so many places to look for primary sources online beyond the links above.
Try a Google search for your topic and one of the following types of primary sources:
Alternatively, just try a search for your topic with the phrase "primary sources".
Is the primary source you're looking at online real? Is it legitimate? Take a moment to find out about the author or owner of the website you're looking at.
Clues about a website in the URL/domain name:
.edu = educational institution
.gov = US government site
.org = organization or association
.com = commercial site
.museum = museum
.net = personal or other site
Clues about a website based on the author/owner:
Who is the author/owner? Try the about link for the site to see who is putting the information on the internet and why. If the author/owner is a museum, archive, library, university or other educational organization or a governmental entity, this a is a good sign for the validity of the site.