"Copyleft#Strong_and_weak_copyleft" . . . . "CopyLEFT" . "free redistribution" . . . "free" . "protective" . "free and open license" . "Copyleft symbol" . . . "copyleft licenses" . "independently for free" . . . "strong copyleft" . "copyleft Licenses" . . "Copyleft movement" . "by-nc-sa" . . "copyleft" . "Copyleft#Symbol" . . . "Copyleft licenses" . . "share-friendly license" . . "copy-left" . "Copyleft" . . . . "non-copyleft" . "Copyleft (reciprocal)" . . . . "Copyleft" . "copy left" . "copying" . "upload" . . "copyleft software" .