MIL-P-21929C (AMENDMENT 1), MILITARY SPECIFICATION: PLASTIC MATERIAL, CELLULAR POLYURETHANE, FOAM-IN-PLACE, RIGID (2 POUNDS PER CUBIC FOOT) (27 MAY 1994)
MIL-P-21929C (AMENDMENT 1), MILITARY SPECIFICATION: PLASTIC MATERIAL, CELLULAR POLYURETHANE, FOAM-IN-PLACE, RIGID (2 POUNDS PER CUBIC FOOT) (27 MAY 1994).