Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe - Blanton, Michael R; Bershady, Matthew A; Abolfathi, Bela; Albareti, Franco D; Allende Prieto, Carlos; Almeida, Andres; Alonso-Garcia, Javier; Anders, Friedrich; Anderson, Scott F; Andrews, Brett; Aquino-Ortiz, Erik; Aragon-Salamanca, Alfonso; et al. (Astronomical Journal, 2017)