1. Introduction

2. The sample

3. Observations

4. Data reduction
4.1. Spectrophotometric accuracy

5. Emission line flux measurements

6. Comparison with the literature
6.1. Comparison with integrated spectra
6.2. Comparison with Hα+[NII] narrow band imaging

7. Analysis
7.1. Ancillary data and the derived physical parameters
7.2. Line diagnostic
7.3. Emission lines equivalent widths
7.4. Balmer decrement
7.5. Underlying Balmer absorption

8. Conclusions