Subanar .
(1), Suryo Guritno
(2), Zanzawi S.
(3), Abdurakhman .
(4)
(1)
Department of Mathematics, Gadjah Mada
University, Jogjakarta, Indonesia., Indonesia,
(2)
Department of Mathematics, Gadjah Mada
University, Jogjakarta, Indonesia.,
(3)
Department of Mathematics, Gadjah Mada
University, Jogjakarta, Indonesia., Indonesia,
(4)
Department of Mathematics, Gadjah Mada
University, Jogjakarta, Indonesia., Indonesia