Trewartha-James, W. H. <br/><br/>
Bulletin of the Institution of Mining and Metallurgy,  ;   No. 138 

 - Londres-XXK :   The Institution of Mining and Metallurgy,   1916. 
 - p. 55-57 :   il. 
 - Mensual 
 - No. 138(Mar.1916) 
 - Bulletin of the Institution of Mining and Metallurgy,  ;   No. 138 .