[2017-09-02]. doi:10.1063/1.3057264. (原始内容存档于2013-09-21). Merrill, Paul W. Stellar spectra of class S. Astrophysical Journal. 1922, 56: 457–82 [2017-09-02]
Eckert. Schwarzschild describes the computational research he did there on stellar models, then turns to his experience during World War II at Aberdeen Proving