TY - RPRT TI - Structural properties of a precast joist concrete floor construction sponsored by the Portland Cement Association AU - Whittemore, Herbert L AU - Stang, Ambrose H AU - Parsons, Douglas E PY - 1940 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS BMS 62 DO - 10.6028/NBS.BMS.62 ER -