OS Books suggestion

[Ezequiel García]

I am looking for some biblographic material for OS learning (mostly for linux). I've read Linux Device Drivers, and I am interested in these:

* The design of unix operating system (Bach)

* Modern operative systems (Tanenbaum)

* Operating Systems design and implementation(Tanenbaum)

I haven't done formal Computer Science studies, and I don't the time to read the three of them, but as I am working very close to the linux kernel, I am trying to sharp my skills a little. 

All books seem very well rated, and the first one is a real classic. I would like to have further suggestions so I can decide myself better.

Thanks.
Ezequiel.