1. Winita Sulandari:
Department of Mathematics, Universitas Gadjah Mada, Indonesia; Study Program of Statistics, Universitas Sebelas Maret, Indonesia
2. Subanar:
Department of Mathematics Universitas Gadjah Mada, Indonesia
3. Suhartono:
Department of Statistics Institut Teknologi Sepuluh Nopember, Indonesia
4. Herni Utami:
Department of Mathematics Universitas Gadjah Mada, Indonesia
5. Muhammad Hisyam Lee:
Department of Mathematical Sciences
Universiti Teknologi Malaysia, Malaysia