@article{Wu2015Energy,
    author = {J. Wu and Y. Zhang and M. Zukerman and Edward K.-N. Yung},
    title = {Energy-Efficient Base Stations Sleep Mode Techniques in Green Cellular Networks: A Survey},
    journal = {IEEE Communications Surveys and Tutorials},
    volume = {17},
    number = {2},
    pages = {803-826},
    month = {second quarter},
    year = {2015}
}