SIMBAD references

Radial velocity data for 40 Cepheid stars obtained with the CORAVEL spectrometer are presented. They represent 1203 individual observations. The mean number of measurements per star is 41, ranging from 10 to 133. For each star, a Fourier analysis has been made and we searched the period that gave the best fit for the velocity curve. When the data covered a sufficiently long time interval, it has been looked for period changes or phase jumps. The results have been compared to those found in the literature; the choice of the best periods is discussed, taking into consideration the uncertainty on the period, the smoothness of the fit and several other parameters. New orbital elements, based on CORAVEL measurements only, are given for DL Cas and W Sgr.