Sharif University of Technology Scientia Iranica 1026-3098 4 1 1997 03 01 Periodic Solution of a Certain Class of Nonlinear Fourth Order Differential Equation 1 7 21754 10.24200/sci.2020.21754 EN B. Mehri Sharif. University of Technology, Tehran, Iran D. Shadman Sharif University of Technology, Tehran, Iran Journal Article 2020 03 02 In this paper the fourth.... https://scientiairanica.sharif.edu/article_21754_f3af38a9500cfc72614a7cb788e5a56b.pdf