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Frommert H; Kronberg C. (2005). "The Milky Way Galaxy". SEDS. Archived from the original on 2011-08-11. Retrieved 2007-05-09.{{cite web}}: CS1 maint: multiple names: authors list (link)
Sale, S. E.; Drew, J. E.; Knigge, C.; Zijlstra, A. A.; Irwin, M. J.; Morris, R. A. H.; Phillipps, S.; Drake, J. J.; Greimel, R.; Unruh, Y. C.; Groot, P. J.; Mampaso, A.; Walton, N. A. (2009). "The structure of the outer Galactic disc as revealed by IPHAS early a stars". Monthly Notices of the Royal Astronomical Society. 402 (2): 713–723. arXiv:0909.3857. doi:10.1111/j.1365-2966.2009.15746.x. S2CID12884630.
Frommert H; Kronberg C. (2005). "The Milky Way Galaxy". SEDS. Archived from the original on 2011-08-11. Retrieved 2007-05-09.{{cite web}}: CS1 maint: multiple names: authors list (link)