Powers T. C. <br/><br/>
air requeriments of frost-resistant concrete / by T. C. Pow-ers. 

 - Chicago : Portland Cement Association, Research Laboratories 
 - 28 p. 
 - Bulletin 33 / Portland Cement Association .
<br/><br/> "Authorized reprint from Proceedings, Highway Research Boar-d, Vol. 29 (1949)".