@article{Lewandowski:06, 
author = {Achim Lewandowski and Marcus Ludl and Gerald Byrne and Georg Dorffner}, 
journal = {J. Opt. Soc. Am. A}, 
keywords = {Halftone image reproduction; Reflection},
number = {8}, 
pages = {1827--1834}, 
publisher = {OSA},
title = {Applying the Yule-Nielsen equation with negative n}, 
volume = {23}, 
year = {2006},
url = {http://josaa.osa.org/abstract.cfm?URI=josaa-23-8-1827},
}