Browsing that article the principles they list are all core aspects of the GTD system. Honestly I really don't see how they've tweaked it to apply to college students, it looks almost identical to the regular GTD system to me. I'm self employed so I don't have a set work schedule either but I find the GTD system applies both to my work and personal life nicely.
In GTD a project is any task that requires more than one step to complete. As a college student projects may be writing a term paper or preparing for an upcoming test. Both of these examples can be managed using GTD.
If you are hesitant to purchase the book I would suggest borrowing it from the library. However after reading it you may want to purchase a copy for yourself. Mine is quite worn as I refer to it often.
Nozbe which is an online tool created to work with the GTD system has some great short videos that you may want to check out. While they talk about the system in the videos they also offer a great overview of the GTD system and how it applies to everyday life. You can find the videos here,
10-Step Simply Get Things Done Course: Nozbe - getting things done gtd software task manager and to-do list for project management and time tracking. Now on Apple iPhone and Mobile Phone!.