कॉपीलेफ्ट भी एक तरह का कॉपीराइट है। इन्हें भी देखें प्रतिलिप्यधिकार अधिनियम बाहरी कड़ियाँ Collection of laws for electronic access from WIPO – intellectual property laws of many countries Copyright from UCB Libraries GovPubs'' About Copyright at the UK Intellectual Property Office A Bibliography on the Origins of Copyright and Droit d'Auteur 6.912 Introduction to Copyright Law taught by Keith Winstein, MIT OpenCourseWare January IAP 2006 UK Copyright Law fact sheet (April 2000) a concise introduction to UK Copyright legislation