You will want to use scholarly sources in research papers and anytime you want verified facts and opinions supported by evidence. One type of scholarly source is peer-reviewed, meaning experts in the field have evaluated and approved the article before publication.
Opinion or editorials articles within scholarly journals are NOT scholarly!
Non-Scholarly sources can be used for finding best practices, current events, popular opinions, easy to understand summaries, and entertainment. These sources are usually not appropriate to use in research papers.
For some research topics, you may want to cite original documents, interviews, artwork, artifacts, novels, poetry, or music. These are all primary sources, which were either created at the time of an event or created by a person who experienced an event. Primary sources offer a unique insight into a particular time or topic.
Examples of primary sources:
Letter
Diary
Photo
Play
Pottery
Novel
Poetry
Autobiography
Financial record
Meeting minutes
Historical Account
Official records (ex. Birth certificate)
Government documents
News recording
Newsletter
Speech
Newspaper
Magazine
Census data
Obituary
Interview
TV show
Advertisement
Music
Book
Political ads
Cars
Architecture
Film
Artwork
Furniture
Coins
Map
Clothing
Memoir