References 

1) https://www.staedtler.com/intl/en/discover/which-materials-are-required-to-create-a-technical-drawing

2) https://en.wikipedia.org/wiki/Technical_drawing

3) Machine Drawing 3rd Edition by K.L Narayana, 2001

4) Technical Drawing 1: Plane and Solid Geometry Book by A. Bankole,1991