6 sources are required, 1 of your references must come from your textbook.
New college students use Google Scholar to complete research tasks in high school, and they hesitate to use other tools in the completion of college-level research tasks.
If this is still you, consider my BIG 3 research approach for scholarly sources:
1. Use library tools first. If we don't have it, go to step 2.
2. Try Google Scholar as a fallback plan. If that doesn't work (like, you hit a paywall)...
3. Use SU Libraries' Interlibrary Loan service when all else fails. If you have citation info for a source you can't get, request it through ILL.