| 1930 CROOK Traffic Signal Projector Patent Print |
| 1930 FRANK Electric Signal Bell Patent Print Art |
| 1930 ELECTRIC SIGNAL LTD Signal Art Print |
| 1930 FRANK Railroad Crossing Signal Patent Print |
| 1930 CRITCHFIELD Warning Signal Patent Print Art |
| 1930 LANDESS HENRY Signal Container Patent Print |
| 1930 ANTHONY Electric Signal Switch Art Print |
| 1930 MCCANN Highway Crossing Signal Patent Print |
| 1930 XAVIER Railroad Signal Lock Patent Print |
| 1930 ROSS OSCAR Check Light Signal Patent Print |
| 1930 DELCO REMY CORP Warning Signal Patent Print |
| 1930 LAMONT JESSE Signal Device Patent Print Art |
| 1930 JEFFERSON GLENN Light Signal Patent Print |
| 1930 EDWARD PETERS Crossing Signal Patent Print |
| 1930 CHAMBERLAND Traffic Signal Patent Print Art |
| 1930 EVERETT Railway Signal Lamp Patent Print |
| 1930 ZAWYRUCHIA LEE Signal Patent Print Art |
| 1930 MAPLES JACK Signal Patent Print Art |
| 1930 FENTRESS Signal Sunken Vessels Art Print |
| 1930 ADLAKE CO Signal Lamp Patent Print Art |
| 1930 ERNEST Railway Crossing Signal Patent Print |
| 1930 KLEIN JOSEPH Signal Device Patent Print Art |
| 1930 LARSON CARL Signal Lamp Patent Print Art |
| 1930 KARL WARTMANN Signal Patent Print Art |