Baek, M., M. B. Lee, J. Park, Y. Cho, and C. Shin. “Design of Greenhouse Control Engine of Optimal to Minimize the Energy Costs”. International Journal of Control and Automation, Vol. 7, no. 1, June 2014, pp. 09 -16, http://sersc.org/journals/index.php/IJCA/article/view/140.