Engelfriet, Arnoud. The best of both worlds. Intellectual Asset Management (IAM) (New Hibernia House, Winchester Walk, London Bridge, London SE1 9AG, United Kingdom: Gavin Stewart). August–September 2006, (19) [2008-05-19]. (原始内容存档于2013-09-14).
Engelfriet, Arnoud. The best of both worlds. Intellectual Asset Management (IAM) (New Hibernia House, Winchester Walk, London Bridge, London SE1 9AG, United Kingdom: Gavin Stewart). August–September 2006, (19) [2008-05-19]. (原始内容存档于2013-09-14).