| 1928 BILLIG FRED Signaling Device Patent Print |
| 1928 BAUGHMAN Railway Signaling Patent Print Art |
| 1928 GILSON Railway Signaling Apparatus Patent |
| 1928 PAIGE Vehicle Lock Signaling Art Print |
| 1928 WILLIAM SPARKS Signaling Device Patent |
| 1928 SPARKSWITHINGTON Signaling Art Print |
| 1928 WHITE GEORGE Signaling Device Patent Print |
| 1928 FORD MOTOR CO Signaling Device Patent Print |
| 1928 SPARKS WITHINGTON CO Signaling Art Print |
| 1928 HERMANN Railway Signaling Device Patent |
| 1928 M H CO Acoustic Signaling Art Print Patent |
| 1928 UNION SWITCH SIGNAL CO Railway Signaling |
| 1928 HOOD Acoustic Signaling Device Patent Print |
| 1928 STEPHENSON Combined Protective Signaling |
| 1928 AYERS FRED Signaling Device Patent Print |
| 1928 SPRAY LESTER Railway Signaling Patent Print |
| 1928 ERNEST Pedal Railway Signaling Art Print |
| 1928 DELCO REMY CORP Signaling Device Patent |
| 1928 KELLOWAY Railway Signaling Patent Print Art |
| 1928 HENRY HOWARD Signaling Device Patent Print |
| 1928 OTTO KERSTEN Signaling Device Patent Print |
| 1928 RALPH GROSS Signaling Apparatus Patent |