The book Der Oracle DBA (Hanser, 2011), which was written in German, is at last available!
I say “at last” because the authors worked on this project for not less than two years.
For my part, I wrote two chapters: Speicherplatzverwaltung and Optimierung. The first one, Speicherplatzverwaltung, is available here. Also available online are the table of content, the preface and the index.