Jahanshahloo, G., Hosseinzadeh Lotfi, F., Maddahi, R., & Jafari, Y. (2012). Efficiency and benchmarking in the presence of undesirable (bad) outputs: A DEA approach. International Journal of Applied Mathematical Research, 1(2), 178-188. https://doi.org/10.14419/ijamr.v1i2.44