Ultimately, your professor sets the expectations for which sources you can and can't use. Generally, scholarly journal articles and scholarly books are more reliable and authoritative than those written for popular audiences.
| Scholarly | Popular | Trade | |
|---|---|---|---|
| Example |  |
 |
 |
| Audience | Academic researchers | General public | Professionals in the business |
| Authors | Unpaid experts and specialists | Paid staff and freelance journalists and writers | Paid staff writers and industry experts |
| Editors | Unpaid editors and peer reviewers | Paid editors | Paid editors |
| Citations | Almost always, many | Rarely, few | Sometimes, few |
