1 2 Gere, J.M.; Timoshenko, S.P. (1996), Mechanics of Materials:Forth edition, Nelson Engineering, ISBN 0534934293 1 2 Beer, F.; Johnston, E.R. (1984), Vector mechanics for engineers: statics, McGraw Hill, pp. 62–76 Citation author surname Beer author given name F. title of source Vector mechanics for engineers: statics year 1984 author1 Beer authors Beer last2 Johnston author2 Johnston first1 F. first2 E.R. pages 62–76 publisher McGraw Hill