1. and , Internat. Conf. Defects in Insulating Crystals, Riga (USSR) 1981 (p. 460).
2. Comment on the Identification of Z Centres in LiF:Mg and LiF:Mg, Ti Single Crystals
3. and , Internat. Conf. Colour Centres in Ionic Crystals, Reading (U.K.) 1971 (Abstr. No. 55).
4. and , Internat. Conf. Colour Centres in Ionic Crystals, (Abstr. No. 77).
5. private communication.