1 - SDSS
2 - Berta et al. (2007)
4 - Swinbank et al. (2005)
8 - UZC catalogue	
16 - IRASpsz
32 - Rowan-Robinson et al. (2013)/Perez-Fournon et al. (2004)
64 - Rowan-Robinson et al. (2013)/Serjeant et al. (2004)
128 - 2MRS
256 - Lacy et al. (2013)