You may be asked to find specific types of sources, for example: primary, peer-reviewed sources.
Primary sources vs Secondary sources: -Primary sources in the sciences means the authors analyzed their own data in their study, rather than summarizing someone else's data.
Examples of primary sources: Randomized Controlled Trial, Cohort, Case Control, Conference Proceedings. Articles often have "structured abstracts," listing Objectives, Methods, Results, Conclusions. Check the Methods section to see if the authors gathered the data themselves or if they just looked at other studies.
-Secondary sources in the sciences means the authors are summarizing other researchers' findings.
Examples of secondary sources: Book chapter, Government report (unless specified that they gathered the data), Literature Review, Systematic review, Meta-analysis. Many websites are also secondary sources, compiling information from multiple sources. If an article, check the Methods section to see if they simply searched for or summarized data from other research.
Peer-reviewed sources: Most scholarly journals have a process by which the submitted articles are reviewed by several experts or "peers" in the field before they are accepted for publication. This process ensures the quality of the research. Thus, it is preferable to cite a peer-reviewed journal over a magazine, trade publication (newsletter), or non-peer-reviewed journal in research.
Some library database (such as EBSCO) have an option to limit search results to only peer-reviewed sources. If this option is not available, when you click on the Find Text@TAMU button to get the PDF of the article, the screen that opens should have a yellow sticky note in the right-hand corner telling you if the article is from a peer-reviewed journal.