Cathedral, forge, and waterwheel : technology and invention in the middle ages 
Gies, Frances. 
 -  Harper Collins Publishers,  1994 
 - 357 p. 
0-06-016590-1
Invention -- History.
609.40902 G455 1994
                        0-06-016590-1
Invention -- History.
609.40902 G455 1994