@inproceedings{luc-99-orat-ab, author = {Andrzej {\L}ukaszewski}, title = {Offsets of Rational Surfaces and Ray Tracing}, booktitle = {Abstracts of the 4th International AFA Conference on Curves and Surfaces}, location = {Saint-Malo, France}, pages = {50--51}, year = 1999, month = jun }