To cite the service as such, we suggest the following BibTeX entry:
@MISC{vo:eiueilewpset,
year=2007,
title={{CDN} VO Server},
author={{PADC}},
url={http://vogate.obs-nancay.fr/__system__/services/root/info},
howpublished={{VO} resource provided by the {CDN} VO Server}
}