Isis Truck Herman Akdag Amel Borgi A symbolic approach for colorimetric alterations. 105-108 2001 EUSFLAT Conf. http://www.eusflat.org/publications/proceedings/EUSFLAT_2001/papers/105_Truck.pdf conf/eusflat/2001 db/conf/eusflat/eusflat2001.html#TruckAB01