Sagara, Keiko. <br/><br/>
Numeral Systems in sign languages across the world. 

 - Osaka-JP :   National Museum Ethnology,   2014. 
 - páginas 5-7 :   ilustraciones blanco y negro 
 - Irregular 
 - No. 39 (Dic. 2014) 
 - Minpaku Anthoropology Newsletter ;   no. 39 .
 - National Museum of Ethnology Osaka. .