Searching Google: Domain searching
Search: politics art site:edu > will return results from educational websites - i.e. www.calarts.edu; www.ucla.edu; www.csun.edu; etc.
You can indicate any domain > site:gov (government); site:org (non-profit), etc.
Search: politics art filetype:pdf > will return only PDFs in your results
You can indicate any type of file
More Google search operators available here
Stanford Encyclopedia of Philosophy
United Nations: Declaration on Granting Independence to Colonial Countries and Peoples, 1960