BibTex format
@article{Sheppard:1997,
author = {Sheppard, CJR and Torok, P},
journal = {OPTIK},
pages = {77--82},
title = {Approximate forms for diffraction integrals in high numerical aperture focusing},
url = {https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1997WZ78000008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb},
volume = {105},
year = {1997}
}