We classify all references into one of three categories. Category one is phenomenon demonstration, category two is books, encyclopedia, discussion and forum posts and category three is published research papers. The three categories offer different perspectives into the problem and have different levels of academic rigour.
These are commonly videos on platforms like YouTube, Facebook etc. The videos show the phenomenon described in the problem statement or one that is similar. Whether the videos accurately depict the problem statement is up to individual interpretations. These references are often created to demonstrate a physical principle qualitatively. Many lack control of key parameters and thus not suitable for scientific analysis.
Books, Encyclopedia, Discussion and Forum Posts
This category contains references from many sources. The accuracy of information in this category can vary. Textbooks and lecture slides/notes are the most accurate. Other professional books and student thesis are generally accurate. Encyclopedia and forum post answers are only sometimes accurate because the primary source of information is often missing. . Student discussion is not a reliable source of information.
This category only contains articles written to academic standards. Most of the articles in this section are published in peer-reviewed journals. A very small proportion of articles are from arXiv. Note that the articles on arXiv is only a preprint and might not be peer-reviewed. But since these articles are written with academic rigour in mind, the information accuracy is still generally better than encyclopedia and forum posts.