Richards, J. (2013). Freehand drawing and discovery: Urban sketching and concept drawing for designers. Wiley.
Lua i Stíl Chicago (17ú heag.)Richards, James. Freehand Drawing and Discovery: Urban Sketching and Concept Drawing for Designers. Hoboken, New Jersey: Wiley, 2013.
Lua MLA (8ú heag.)Richards, James. Freehand Drawing and Discovery: Urban Sketching and Concept Drawing for Designers. Wiley, 2013.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.