Exchange of bibliographical references on coal production methods  Echange de renseignements bibliographiques surles methodes de production = (Romanized characters).  Echange de renseignements bibliographiques surles methodes de production = (Romanized characters).  [microform] = 

 - Geneva :  United Nations,  1957. 
 - United Nations. [Document] ;  E/ECE/300, E/ECE/Coal/128 .
 - Document (United Nations) ;  E/ECE/300, E/ECE/Coal/128 .
<br/><br/> United Nations publication. Sales no.: 1957.II.E/Min. 25. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Coal mines and mining -- Bibliography.--Coal mines and mining -- Bibliography.