Gateway drug theory:

A. This article, although concise, is a good article in itself. It references several different reliable sources that date all the way back to 1974-2016. The different sections of the article all relate to the main idea.

B. This article would be a good background for my second source because it discusses similar things having to do with gateway drugs, such as trends and risk factors. It also has lots of different information pertaining to gateway drugs which will allow me to expand my paper.