Corresponding Author

Paper:	idn142
Name:	G.B. Suparta
Company:	Gadjah Mada University Dept. of Physics
Address:	Sekip MIPA Utara Yogyakarta 55281
Country:	Indonesia
Phone:	+62 274 887507
Fax:	+62 274 513339
Email:	bayus@ugm.ac.id