Balmer, G. G. <br/><br/>
Laboratory studies of the skid resistance of concrete / by -G. G. Balmer and B. E. Colley. 

 - Skokie, Illinois : atories, Development Department 
 - 28 p. 
 - Bulletin D109 / Portland Cement Association, Research and D-evelopment Laboratories, Development Department .
<br/><br/> "Authorized reprint from copyrighted Journal of Materials, - Vol. 1, No. 3, 536-559 (September 1966) American Society o-f Testing and Materials".