T. E.S. EL-SHAPEI. "AN EXPERIMENTAL STUDY OF THE FRICTION TORQUE OF THRUST BEARINGS COVERED BY SOFT METAL FILMS WHEN OPERATIAG TN VACUUM", The International Conference on Applied Mechanics and Mechanical Engineering, 2, 2nd Conference on Applied Mechanical Engineering., 1986, 279-289. doi: 10.21608/amme.1986.57053