Query Results from the ADS Database Retrieved 1 abstracts, starting with number 1. Total number selected: 1. @ARTICLE{1973ARA&A..11...29M, author = {{Morgan}, W.~W. and {Keenan}, P.~C.}, title = "{Spectral Classification}", journal = {\araa}, year = 1973, volume = 11, pages = {29}, doi = {10.1146/annurev.aa.11.090173.000333}, adsurl = {http://adsabs.harvard.edu/abs/1973ARA%26A..11...29M}, adsnote = {Provided by the SAO/NASA Astrophysics Data System} }