Nicholls, H. E. <br/><br/>
A pioneer Bucket Dredge in Northern Nigeria. 

 - Londres-XXK :   The Institution of Mining and Metallurgy,   1916. 
 - p. 31-35 
 - Mensual 
 - No. 138(Mar.1916) 
 - Bulletin of the Institution of Mining and Metallurgy,  ;   No. 138 .
<br/><br/><br/>Espaņol.