# References for trascendental number theory

I'm an undergraduate student in Mathematics who has to do a short essay about very basic Trascendental Number theory. In particular, I have to study the proof of trascendence of $e$ and $\pi$, and I was looking for some more advanced theorem to study: unfortunately all the material I find is too advanced/requires too much knowledge about analytic number theory. Do you know some introductive book about this subject/some -not too difficult- result I can study?

2. Notes at http://www.math.nus.edu.sg/~urops/Projects/transcendental.pdf for transcendence of $\pi$.
3. Notes at http://www.math.utk.edu/~freire/m400su06/transcendence%20of%20e.pdf for transcendence of $e$.