* [https://web.archive.org/web/20130616220554/http://www.pentrace.net/penbase/Data_Returns/full_article.asp?id=406] Giovanni Abrate article on Pen Trace
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* http://www.museomils.it/index.php?it/117/lus
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* [http://www.museomils.it/index.php?it/117/lus] Company page on the MILS website