Gerhard, Ortwin Optical and Interpretative Astronomy, MPI for Extraterrestrial Physics, Max Planck Society;
Bhattacharya, S., Arnaboldi, M., Hartke, J., Gerhard, O., Comte, V., McConnachie, A., et al. (2019). The survey of planetary nebulae in Andromeda (M 31) - I. Imaging the disc and halo with MegaCam at the CFHT. Astronomy and Astrophysics, 624: A132. doi:10.1051/0004-6361/201834579.