1. 1. S P Sukhatme, J K Nayak,”Solar energy Principle of Thermal collection and storage”
   2. Jan Holterman, Pim Groen,”An introduction to Piezoelectric materials and application”
   3. Richard Hantula,”How solar panel work”, Science curriculum Resource Teacher
   4. “http://whatis.techtarget.com/definition/piezoelectricit y”
   5. Power Generation for Auto Street Light Using PZT”, Mrinmoy Dey, Tawhida Akand and Sadeka Sultana, Proceedings of 2015 3rd International Conference on Advances in Electrical Engineering 17-19 December, 2015, Dhaka, Bangladesh.
   6. “An Architecture for Traffic Sign Management in Smart Cities”, Everton R. Lira, Enrique Fynn, Paulo R. S. L. Coelho, Luis F. Faina, Lasaro Camargos,Rodolfo S. Villac and Rafael Pasquini, Faculty of Computing (FACOM/UFU), Uberl andia – MG – Brazil.
   7.  ” Smart Traffic Light Control System” Bilal Ghazal, Khaled EIKhatib, Khaled Chahine, Mohamad Kherfan, School of Engineering Lebanese International University (LIU) Beirut, Lebanon
   8. “A new intelligent control terminal of solar street light”, Wang Guijuan, Wang Zuoxun, School of Information and Control Engineering Shandong Institute of Light Industry Jinan, China
   9.  ”A review on energy harvesting from roads”, Andriopoulou Symeoni,,MSc “Environmental Engineering & Sustainable Infrastructure
   10. “Shape Effect of Piezoelectric Energy Harvester on Vibration Power Generation”, Amat A. Basari, Sosuke Awaji, Song Wang, Seiji Hashimoto, Shunji Kumagai, Kenji Suto, Hiroaki Okada, Hideki Okuno, Bunji Homma, Wei Jiang, Shuren Wang,Division of Electronics and Informatics, Gunma University, Kiryu, Gunma, Japan,School of Hydraulic, Energy and Power Engineering, Yangzhou University, Yangzhou, China