Light: The Shape of Space: Designing with Space and Light Escrito por Lou Michel

http://books.google.es/books?id=PhNY1sJfAE8C&pg=PA33&lpg=PA33&dq=luminance+ratios&source=bl&ots=sRvBqTO8yV&sig=HOM-bT3dM3XYb0wna61flO_IfN0&hl=es&ei=wovpS8ruGMGgsQbekqGyCA&sa=X&oi=book_result&ct=result&resnum=9&ved=0CEwQ6AEwCA#v=onepage&q=luminance%20ratios&f=false