TY - RPRT TI - Circular of the Bureau of Standards no. 50 2nd edition: national standard hose couplings and fittings for public fire service PY - 1917 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS CIRC 50e2 DO - 10.6028/NBS.CIRC.50e2 ER -