http://diananuramalina.blogspot.com/2012/06/isd-dan-ips.html
http://lonelyfe.blogspot.com/2013/03/pengertiantujuanisd-dan-ips-dan-ruang_14.html
http://zakiajamaldotcom.wordpress.com/2012/11/21/pengertian-isd-dan-ips
http://fahmifadly23.wordpress.com/2013/04/03/persamaan-dan-perbedaan-isd-dan-ips/
aisyahtyasmaharani 