+}
+
+@incollection{ref232,
+ title={A review on localization in wireless sensor networks},
+ author={Kuriakose, Jeril and Joshi, Sandeep and Raju, R Vikram and Kilaru, Aravind},
+ booktitle={Advances in signal processing and intelligent recognition systems},
+ pages={599--610},
+ year={2014},
+ publisher={Springer}
+}
+
+@article{ref233,
+ title={Localization techniques in wireless sensor networks},
+ author={Alrajeh, Nabil Ali and Bashir, Maryam and Shams, Bilal},
+ journal={International Journal of Distributed Sensor Networks},
+ volume={2013},
+ year={2013},
+ publisher={Hindawi Publishing Corporation}
+}
+
+@inproceedings{ref234,
+ title={UREA: Uncovered region exploration algorithm for reorganization of mobile sensor nodes to maximize coverage},
+ author={Nene, Manisha J and Deodhar, Rajendra S and Patnaik, Lalit M},
+ booktitle={6th IEEE International Conference on Distributed Computing in Sensor Systems Workshops (DCOSSW)},
+ pages={1--6},
+ year={2010},
+ organization={IEEE}
+}
+
+@inproceedings{ref235,
+ title={Mobility improves coverage of sensor networks},
+ author={Liu, Benyuan and Brass, Peter and Dousse, Olivier and Nain, Philippe and Towsley, Don},
+ booktitle={Proceedings of the 6th ACM international symposium on Mobile ad hoc networking and computing},
+ pages={300--308},
+ year={2005},
+ organization={ACM}
+}
+
+@article{ref236,
+ title={Localization and coverage for high density sensor networks},
+ author={Bahi, Jacques M and Makhoul, Abdallah and Mostefaoui, Ahmed},
+ journal={Computer Communications},
+ volume={31},
+ number={4},
+ pages={770--781},
+ year={2008},
+ publisher={Elsevier}
+}
+
+@article{ref237,
+ title={Hilbert mobile beacon for localisation and coverage in sensor networks},
+ author={Bahi, Jacques M and Makhoul, Abdallah and Mostefaoui, Ahmed},
+ journal={International Journal of Systems Science},
+ volume={39},
+ number={11},
+ pages={1081--1094},
+ year={2008},
+ publisher={Taylor \& Francis}
+}
+
+@article{ref238,
+ title={Heuristic optimization methods in econometrics},
+ author={Gilli, Manfred and Winker, Peter},
+ journal={Handbook of computational econometrics},
+ pages={81--119},
+ year={2009},
+ publisher={Wiley}
+}
+
+@article{ref239,
+author = {Hung, Ka-Shun and Lui, King-Shan},
+title = {Perimeter Coverage Scheduling in Wireless Sensor Networks Using Sensors with a Single Continuous Cover Range},
+journal = {EURASIP Journal on Wireless Communications and Networking },
+volume = {2010},
+year = {2010}
+}
+
+@article{ref240,
+ title={Solving the cell suppression problem on tabular data with linear constraints},
+ author={Fischetti, Matteo and Salazar, Juan Jos{\'e}},
+ journal={Management Science},
+ volume={47},
+ number={7},
+ pages={1008--1027},
+ year={2001},
+ publisher={INFORMS}