Use the 'Lateral Reading' tutorial below to learn more about assessing your sources:
With every source you find - regardless of where it comes from - you MUST assess its quality to determine if it is worthy of being included in your research. Generally speaking, academic assignments ask you to first consult scholarly, peer-reviewed research from reputable publishers.
*Note that you should always follow the instructions given to you by your professor. There are certainly instances in which other materials are valuable for scientific research!