To cite the service as such, we suggest the following BibTeX entry:
@MISC{vo:posse_siap, year=2019, title={Palomar survey digitized by {MAMA}}, author={J. Guibert on behalf of {PADC}}, url={http://voparis-tap-astro.obspm.fr/posse/q/siap/info}, howpublished={{VO} resource provided by the {PADC} {TAP} Server on voparis-tap-astro.obspm.fr} }