The proceedings for this conference, "Adapting to the Atmosphere", have been published by the Institute of Physics, Journal of Physics: Conference Series, Volume 595.
Journal of Physics: Conference Series uses article numbers, so if you wish to cite a paper from these proceedings you will need to know the article number and the volume 595. For example, the first paper in these proceedings would be cited as:
Günter Auzinger 2015 J. Phys.: Conf. Ser. 595 012001