Wulandari, Astrid, Sri Waluyo, and Dwi Dian Novita. 2013. “Prediction of Self Life of Kemplang Crackers Packaged in Polypropylene Plastick With Thickneses”. Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) 2 (2). http://jurnal.fp.unila.ac.id/index.php/JTP/article/view/256.