Hedstrom, R. O. <br/><br/>
Load test of Patterned concrete masonry walls / by R. O. He-dstrom. 

 - Skokie, Illinois : atories, Development Department 
 - [28] p. 
 - Bulletin D41 / Portland Cement Association, Research and De-velopment Laboratories, Development Department .
<br/><br/> "Authorized reprint from copyrighted Journal of the America-n Concrete Institute, april, 1961, Proceedings vol. 57 p. 1-265."