Merrill, P. W.; Deutsch, A. J. & Keenan, P. C. (1962). "Absorption Spectra of M-Type Mira Variables". Astrophysical Journal. 136: 21. Bibcode:1962ApJ...136...21M. doi:10.1086/147348.
Merrill, P. W.; Deutsch, A. J. & Keenan, P. C. (1962). "Absorption Spectra of M-Type Mira Variables". Astrophysical Journal. 136: 21. Bibcode:1962ApJ...136...21M. doi:10.1086/147348.