Maybe your teacher said academic or peer-reviewed?
Some (but perhaps not all) of these things may be present.
1. The publisher specializes in scholarly publications (such as Sage Publications). You can Google the publisher to find out more.
2. The author or authors are credentialed.
3. There's an abstract.
A literature review summarizes and synthesizes the research an author has done to lay the foundation for their work. It helps you, the reader, understand what scholarship the author has consulted, and which scholars have influenced their thinking in which ways.
If the author conducted a study, they will likely include a section that details the research strategy that they followed to achieve their results. This assures the readers (and their peer reviewers) that they pursued ethical means of research, and outlines the steps they created and followed to get there. It will also inform the reader of the types of methods they chose and why, which can help the reader understand the mechanics of their study and the results.
Scholarship implies research. A heavy reference page is a good indicator that the author or authors did a fair amount of research to establish credibility and participated in a significant and serious scholarly conversation. While research can take many forms (a scientific study, for example), a published scholarly article won't be complete without evidence that the author or authors consulted with peers and experts to shape the course of their research. This can result in agreement, or argument -- hence the nature of a conversation. When you do college-level writing, you too are participating in the ongoing conversation.