1 INTRODUCTION

2 DATA SETS
2.1 RR Lyrae sample from WASP and ASAS surveys
2.2 Globular cluster RRab stars
2.3 Fourier parameters of RR Lyrae stars located in the LMC, SMC and GB

3 PHYSICAL PARAMETERS DETERMINATION

4 LIGHT-CURVE PROPERTIES OF REGULAR AND MODULATED RRAB STARS

5 DISCUSSION ON PHYSICAL PARAMETERS
5.1 Remarks on period distribution
5.2 Metallicity of non-modulated and Blazhko stars
5.3 Absolute magnitude and mean colours
5.4 Short-period metal-rich variables

6 SUMMARY AND CONCLUSIONS