To cite the service as such, we suggest the following BibTeX entry:
@MISC{vo:eissdpulohlu, year=2016, title={Thumbnails service for {VOTT}}, author={Demleitner, M.}, url={https://dc.zah.uni-heidelberg.de/vott/q/thumbnails/info}, howpublished={{VO} resource provided by the {GAVO} Data Center} }