Nice post. I learn something new and challenging on sites I stumbleupon everyday. It will always be useful to read content from other authors and practice a little something from other web sites.

INDEXED BY:

         

This work is licensed under a Creative Commons Attribution 4.0 International License. 

CSRID Journal Editor's Office:

Universitas Potensi Utama. Jl. K.L. Yos Sudarso Km 6,5 No.3-A Telp. (061) 6640525 Ext. 214 Tanjung Mulia Medan 20241