* [https://web.archive.org/web/20050501152004/http://www.pentrace.net/penbase/Data_Returns/full_article.asp?id=307&tname=Ron+Dutcher+on+Pens] Articolo su Pen Trace (archive.org) | * [https://web.archive.org/web/20050501152004/http://www.pentrace.net/penbase/Data_Returns/full_article.asp?id=307&tname=Ron+Dutcher+on+Pens] Articolo su Pen Trace (archive.org) |