Litvin, Albert. <br/><br/>
penetration test for determining the compressive strength o-f low-density concrete / by Albert Litvin and Cleaver H. Br-inkerhoff 

 - Skokie, Illinois : atories, Development Department 
 - [16] p. 
 - Bulletin D98 / Portland Cement Association, Research and De-velopment Laboratories, Development Department .