+@article{Deng2012,
+ title={Transforming Area Coverage to Target Coverage to Maintain Coverage and Connectivity for Wireless Sensor Networks},
+ author={Xiu Deng and Jiguo Yu, Dongxiao Yu and Congcong Chen},
+ journal={International Journal of Distributed Sensor Networks},
+ volume={2012},
+ year={2012},
+ ee = {http://dx.doi.org/10.1155/2012/254318}
+}
+
+ @inproceedings{jaggi2006,
+ title={Energy-efficient Connected Covereage in Wireless Sensor Networks},
+ author={N. Jaggi and A.A. Abouzeid},
+ booktitle={Proceeding of 4th Asian International Mobile Computing Conference AMOC2006},
+ year={2006}
+}
+
+@INPROCEEDINGS{5714480,
+author={Xiaofei Xing and Jie Li and Guojun Wang},
+booktitle={Mobile Ad-hoc and Sensor Networks (MSN), 2010 Sixth International Conference on},
+title={Integer Programming Scheme for Target Coverage in Heterogeneous Wireless Sensor Networks},
+year={2010},
+month={Dec},
+pages={79-84},
+keywords={energy conservation;integer programming;wireless sensor networks;ETCA;clustered configurations;clusterheads;energy first algorithm;energy-efficient target coverage algorithm;heterogeneous wireless sensor networks;integer programming;network lifetime;polytype target coverage;sensor node;Algorithm design and analysis;Clustering algorithms;Energy consumption;Logic gates;Sensors;Simulation;Wireless sensor networks;Heterogeneous wireless sensor networks;network lifetime;optimization;target coverage},
+doi={10.1109/MSN.2010.18},}
+
+@article{Yang2014,
+ title={A Maximum Lifetime Coverage Algorithm Based on Linear Programming},
+ author={Mengmeng Yang and Jie Liu},
+ journal={Journal of Information Hiding an dMultimedia Signal Processing, Ubiquitous International},
+ volume={5},
+ number={2},
+ pages={296-301},
+ year={2014}
+}