من فضلكم احتاج مساعدة

[خالد الهواري]

F. P. Bowden and D. Tabor. The Friction and Lubrication of Solids -
Part I. Clarendon Press, Oxford, 1950.

https://global.oup.com/academic/pro...cation-of-solids-9780198507772?cc=my&lang=en&