Primary sources can be tricky. Whether a source is primary depends on how you use it. A primary source is a written text, artifact, or other original creation upon which you focus your analysis and interpretation. For example, an article that analyzes a book, song, or society would be considered a secondary source. However, that article could function as a primary source--if you are analyzing the ideas of the author of that article, then it functions as a primary source. So anything could function as a primary source--just consider how you are using it: if it's the object of your analysis, then it's a primary source.
A secondary source is a work that interprets or analyzes an historical event or phenomenon. It is generally at least one step removed from the event is often based on primary sources. Examples include: scholarly or popular books and articles, reference books, and textbooks.
Tertiary sources are encyclopedias, dictionaries, textbooks and other reference materials that provide broad overviews of particular topics. Where secondary sources summarize and interpret an event or phenomenon, tertiary sources summarize and interpret other resources. They can be a great place to begin studying unfamiliar topics.