Kardos P, Palágyi K. On topology preservation for hexagonal parallel thinning algorithms. In: Aggarwal JK, Barneva RP, Brimkov V E, Koroutchev KN, Korutcheva ER, editors. Combinatorial Image Analysis (IWCIA). Madrid, Spain: Springer Verlag; 2011. 3. p. 31-42p.  (Lecture Notes in Computer Science).