+}
+
+@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={Distributed Computing in Sensor Systems Workshops (DCOSSW), 2010 6th IEEE International Conference on},
+ 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}
