"National X-Ray Reflector Company." . . "National X-Ray Reflector Company. Engineering Department." . . . . . . . . "Lighting from concealed sources : a practical treatment of lighting problems to obtain satisfying illumination & individual effects without exposed light sources" . "Lighting from concealed sources a practical treatment of lighting problems to obtain satisfying illumination & individual effects without exposed light sources"@en . . "Lighting from concealed sources : a practical treatment of lighting problems to obtain satisfying illumination and individual effects without exposed light sources"@en . . . . . . .