− | Brevetto per una penna a sfera. Riferimenti a {{MentionPatent|US|1850086}}, {{MentionPatent|US|1874110}}, {{MentionPatent|US|2153488}}, {{MentionPatent|US|2449218}}, {{MentionPatent|US|2468258}}, {{MentionPatent|US|2500979}}, {{MentionPatent|US|2536923}} e {{MentionPatent|US|2580753}} ed inoltre {{MentionPatent|FR|628418}}, {{MentionPatent|IT|434348}}, {{MentionPatent|AU|128697}}, {{MentionPatent|FR|962297}}, {{MentionPatent|GB|641595}}. | + | Brevetto per una penna a sfera. Riferimenti a {{MentionPatent|US|1850086}}, {{MentionPatent|US|1874110}}, {{MentionPatent|US|2153488}}, {{MentionPatent|US|2449218}}, {{MentionPatent|US|2468258}}, {{MentionPatent|US|2500979}}, {{MentionPatent|US|2536923}} e {{MentionPatent|US|2580753}} ed inoltre {{MentionPatent|FR|628418}}, {{MentionPatent|IT|434348}}, {{MentionPatent|AU|128697}}, {{MentionPatent|FR|962297}}, {{MentionPatent|GB|641595}}. |