(1) Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia (Fax: +386-61/219-385, 123-54-00; E-mail: boris.majaron@ijs.si), SI;(2) University Dental Clinic, Zaloška 2, SI-1000 Ljubljana, Slovenia, SI
Abstract:
Received: 25 March 1997/Revised version: 15 October 1997