Khorramabadi, M. , Nezamabadi, A.. "Vibration Analysis of Functionally Graded Engesser- Timoshenko Beams Subjected to Axial Load Located on a Continuous Elastic Foundation". World Academy of Science, Engineering and Technology, Open Science Index 94, International Journal of Mechanical and Mechatronics Engineering, (2014), 8(10), 1723 - 1726.