HAL Exoskeleton, Accessed on 22 December 2018; https://www.cyberdyne.jp/english.
 SuitX Exoskeleton, Accessed on 22 December 2018; https://www.suitx.com.
 Honda Exoskeleton, Accessed on 22 December 2018; https://world.honda.com/Walking-Assist.
 Kardan I, Akbarzadeh A (2017) Agility enhancement using an assistive controller for exoskeleton robots. Modares Mechanical Engineering 17(9): 119-129. (in Persian)
 Irmscher C, Woschke E, May E, Daniel C (2018) Design, optimisation and testing of a compact, inexpensive elastic element for series elastic actuators. Med Eng Phys 52: 84-89.
 Veneman JF, Ekkelenkamp R, Kruidhof R, van der Helm FCT, van der Kooij H (2006) A series elastic- and bowden-cable-based actuation system for use as torque actuator in exoskeleton-type robots. Int J Robot Res 25(3): 261-281.
 Carpino G, Accoto D, Sergi F, Luigi N, Tagliamonte E Guglielmelli (2012) A novel compact torsional spring for series elastic actuators for assistive wearable robots. J Mech Design 134(12); 121002-121002.
 Lagoda C, Schouten AC, Stienen AHA, Hekman EEG, Kooij HVD (2010) Design of an electric series elastic actuated joint for robotic gait rehabilitation training. 3rd IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics 21-26.
 Chen L, Ding H, Fu T, Li J, Shao L (2018) Design and impedance control of the integrated rotary compliant joint. Adv Mech Eng, Springer Singapore 1125-1140.
 Byrvan H, Sugar T, Vanderborght B, Hollander K, Lefeber D (2009) Review of actuators with passive adjustable compliance/controllable stiffness for robotic applications. Ieee Robot Autom Mag 81-94.
 Accoto D, Carpino G, Sergi F, Tagliamonte NL, Zollo L, Guglielmelli E (2013) Design and characterization of a novel high-power series elastic actuator for a lower limb robotic orthosis. Int J Adv Robot Syst 10(10): 359.
 Taherifar A, Vossoughi G, Selk Ghafari A (2017) Identification and torque control of series elastic actuator of lower limb extremity exoskeleton. Modares Mechanical Engineering 17(8): 1-8. (in Persian)
 dos Santos WM, Caurin GAP, Siqueira AAG (2017) Design and control of an active knee orthosis driven by a rotary series elastic actuator. Control Eng Pract 58: 307-318.
 Paine N, Mehling Joshua S, Holley J, Radford A Johnson NG, Fok CL, Sentis L (2015) Actuator control for the NASA‐JSC valkyrie humanoid robot: A decoupled dynamics approach for torque control of series elastic robots. J Field Robot 32(3): 378-396.
 Choi W, Won J, Lee J, Park J (2017) Low stiffness design and hysteresis compensation torque control of SEA for active exercise rehabilitation robots. Auton Robot 41(5): 1221-1242.
 Bing C, Xuan Z, Hao M, Ling Q, Wei-Hsin L (2017) Design and characterization of a magneto-rheological series elastic actuator for a lower extremity exoskeleton. Smart Mater Struct 26(10): 105008.
 Bovi G, Rabuffetti M, Mazzoleni P, Ferrarin M (2011) A multiple-task gait analysis approach: Kinematic, kinetic and EMG reference data for healthy young and adult subjects. Gait Posture 33(1): 6-13.
 Maxonmotor, Accessed on 22 December 2018; https://www.maxonmotor.com/maxon/view/content/index.
 HarmonicDrive, Accessed on 22 December 2018; http://www.harmonicdrive.net/.
 Au S, Berniker M, Herr H (2008) Powered ankle-foot prosthesis to assist level-ground and stair-descent gaits. Neural Networks 21(4): 654-666.