Recommended practice for selecting proportions for structur-al lightweight concrete (ACI 613A-59) / ACI Committe 613 

 - Detroit, Mich. : American Concrete Institute 
 - 10 p. 
<br/><br/> "Adopted as standard of the American Concrete Institute at -its 55th Annual Convention, feb.24, 1959, as reported by Co-mmitte 613 ; ratified by letter ballot june 1, 1959".