Since I did several things for the first time during my DREU (such as using CSS to create my website, making a poster, and writing an academic paper), I decided to reference sources I found useful during the summer so that future DREU participants may refer to it. From these sources, what I found most useful was first looking at examples of what I needed to create to get an idea of what needs to be done. In addition to these resources, it was also very helpful to get feedback from other REU students and graduate student mentors.
When looking for resources or papers to reference when you're writing your final paper, you
should take advantage your home university's and DREU university's database resources.
All the resources below are found online for free. I was even able to find the book I
referenced for HTML/CSS free since I had access to the IU databases.