TITLE: Recommended second textbook for dynamical systems?
QUESTION [10 upvotes]: I recently finished a course on dynamical systems supplemented by Strogatz's textbook. There are a few parts of the book that we didn't cover (in particular, the material on fractals), but the material that was covered was taught with a bit more detail than presented in Strogatz alone.
What's a good general dynamical systems textbook to "graduate" on to? Preferably, the book should not skimp out on theory and proofs. 
I don't expect it to be self-contained in terms of topology material, but it would be nice if it were self-contained otherwise. 
I don't mind books that skimp out on theory and proofs, if they otherwise present material in a unique way. Please write a little about why you recommand a particular textbook.
Some relevant M.SE questions:
Textbook Recommendation: Topological Dynamics

REPLY [2 votes]: Two books you might consider are:

Perko's Differential Equations and Dynamical Systems published by Springer.
Guckenheimer, J and Holmes, P., Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields also published by Springer.