Recently I had to recreate the section of the website that described the principle of repetition in the learning process. It is something that I personally have used in my own studies over the years and built my own learning system (Memorize-It) around how I learn, knowing that there are many others that use flashcards like I do. In automating this learning process I was able to increase the speed at which I was learning.
In searching for case studies on repetition, the one I found most interesting was The Dana Foundation study on Better Teaching Through Brain Biology. It says: "Without this step of converting new learning to long-term memory-through repetition and elaboration, students are unlikely to be able to use it for a lifetime." The Dana Foundation is a non-profit organization interested in brain science, immunology and arts education. The article I found is a very interesting discussion on the learning process.