Some results of a spectroscopic study of the atmosphere of 31 Cygni
A statistical study of pulsating stars.Fourth paper: The variables in Messier 3
A statistical study of pulsating stars.second paper: The irregular variable A.R. Her
A statistical study of pulsating stars. Third paper: The variable stars in Messier 5
Note On a Generalization of Schwarz' Lemma
A statistical study of pulsating stars.Seventh paper: The variables in M 2
Report on the observation of iron dust
A statistical study of pulsating stars. First paper: The variable stars in a Centauri