PRACE DOKTORSKIE _ FINLANDIA 299,236 SORSA TIMO Human leukocyte collagenase : purification, activation and its role in periodontal collagen degradation: academic dissertation / Timo Sorsa ; Medical Facult-y of the University of Helsinki. - Helsinki : [Yliopistop paino], 1989. - [2], 62 s. ; 30 cm Summ. ISBN 952-90102-8-1