What if and article is from a conference proceedings?
If an article appears in conference proceedings rather than a journal, you will need to determine if it was a peer-reviewed conference.
To do so, conduct a Google search using the conference name and the year it was held. On the official website for the conference, look for pages titled Call for Proposals, or search for Submission Information. These pages will generally state if the conference was a peer-reviewed event.
If it was a peer-reviewed conference, then you can consider your article peer-reviewed.