Many thanks to Timothy C. Cahill, Timothy P. Lighthiser and Rosa Franco for their replies to my query. Alberto Pelissero via Belvedere 51 10028 Trofarello (TO) I T A L Y tel. +39-11-670.3757 (Dept. of Oriental Studies, Turin Univ.) fax +39-11-670.3604 (Dept. of Oriental Studies, Turin Univ.)