A question about legionary helmet

[liuliuliu]

Good day,my friends.
I want to know who designs Legionary helmet,and the process in late republic period.
In fact,I suppose that the legionary craftsmen or blacksmiths based the helmets on soldiers'experience of war.That's my view.Well,somebody points that the blacksmiths may only be in charge of repairing armors,which could be mostly made by blacksmith workshop in big cities.
In a word,I need help,something detailed about the logistics of legionary armors,helmets is very important to my paper.Do you have any books recommended?I would be deeply grateful.

[Flavivs Aetivs]

In terms of Helmet Production, Armor Production, and Blacksmithing Techniques I recommend D. Sim and J. Kaminski's Roman Imperial Armour.

http://www.amazon.com/Roman-Imperial-Arm...1842174355

[liuliuliu]

I have searched all day,may anyone offer to me a PDF of D. Sim and J. Kaminski's Roman Imperial Armour?I only want to know who and where produce the legionary helmets from BC100~AD100.
I am a Chinese student and can not get information of this book via normal ways.Please help me,I would be appreciated.