1. Introduction

2. Programme stars

3. Observations and data reduction
3.1. SPITZER
3.2. TIMMI2

4. Spectral energy distribution

5. General overview
5.1. Silicate dust features: Identification
5.2. Mean spectra and complexes

6. Analysis: Profile fitting

7. Full spectral fitting
7.1. Method
7.2. Results
7.3. Correlations

8. Discussion
8.1. Comparison with young stellar objects

9. Conclusions