Keywords: active galactic nuclei, X-ray surveys, photometric redshifts, spectroscopy, XMM-Newton.

1. INTRODUCTION

2. OBSERVATIONS AT THE AZT-33IK TELESCOPE WITH THE LOW- AND MEDIUM-RESOLUTION ADAM SPECTROGRAPH

3. RESULTS

3.1. The Quasar 3XMM J125329.4+305539 at $z=5.08$

3.2. Remarks on Individual Objects

4. CONCLUSIONS