|Note_en=Advertising for the [[Parker 51|51]] model, citing also the [[Parker 21|21]], [[Parker 41|41]] and [[Parker 61|61]] modesl. {{OnBack|File:1957-Parker-51-Set-Rear.jpg}} | |Note_en=Advertising for the [[Parker 51|51]] model, citing also the [[Parker 21|21]], [[Parker 41|41]] and [[Parker 61|61]] modesl. {{OnBack|File:1957-Parker-51-Set-Rear.jpg}} |