Although artificial indirect lighting dates back twenty-five years or more, it was not very extensively patronized until after 1906 when the advent of the more efficient Mazda B lamp made its commercial use possible. At once comparisons were made between the direct and the indirect systems on various points.
Proceedings of the Iowa Academy of Science
©1922 Iowa Academy of Science, Inc.
"A Comparison of Intensities Required under Direct and under Indirect Lighting Systems,"
Proceedings of the Iowa Academy of Science, 29(1), 141-146.
Available at: https://scholarworks.uni.edu/pias/vol29/iss1/29