List of Articles Nonlinear differential equatio Open Access Article Abstract Page Full-Text 1 - Determination of the amplitude-frequency for strongly nonlinear oscillator by two approximate analytical techniques Amir Ayazi Hadi Ebrahimi Khah 10.1186/2251-7235-7-38 Open Access Article Abstract Page Full-Text 2 - The comparison of homotopy perturbation method with finite difference method for determination of maximum beam deflection Masoud Saravi Martin Hermann Hadi Ebrahimi Khah 10.1186/2251-7235-7-8 Open Access Article Abstract Page Full-Text 3 - Existence of fixed points for generalized α-admissible Geraghty and application to solution of nonlinear differential equations Babak Mohammadi Vahid Parvaneh Farhan Golkarmanesh Open Access Article Abstract Page Full-Text 4 - Analytical Solution of Steady State Substrate Concentration of an Immobilized Enzyme Kinetics by Laplace Transform Homotopy Perturbation Method Devipriya Ganeshan