"Archival" sources (or contemporary sources) are sources that were published in the 1920s. Likely, you will be looking at book reviews, letters, or newspaper interviews/articles with the authors. The sources here should help you get started - but be careful to make use of the date limiter options!
Many of these databases also include biographical information and contemporary reviews (You will likely notice the duplication). So here are some quick questions to ask yourself when identifying scholarly sources. If you can answer "yes" to all of these questions, you are likely looking at a scholarly source.
You'll also want to consider the elements of the CRAAP test - high quality scholarly articles should score especially high in Authority, Accuracy, and Purpose.
And if you are unsure, you can always ask your professor or your librarians!