Westerlund, Bengt <br/><br/>
Luminosity Effects and Colour-Equivalents as Measured in Short Stellar Spectra 

 - Stockholm :   Almquist & Wiksell,   1953. 
 - 50 p. ;   14 cm. 
 - Kungl. Svenska Vetenskapsakademiens handlingar. ;   band 4, nš 6 .
<br/><br/> lll- Summary of classification criteria investigation of region of the open cluster in Coma Berenices.