@article{Sherif2008, 
author = {Sherif, S. S. and Foreman, M. R. and T\"{o}r\"{o}k, P.}, 
journal = {Opt. Express}, 
pages = {3397--3407}, 
title = {Eigenfunction expansion of the electric fields in the focal region of a high numerical aperture focusing system}, 
volume = {16}, 
year = {2008},
doi = {10.1364/OE.16.003397},
}