(:h2 "References")
(:ul
(:li
- ((:a :href "http://solo.colorado.edu/~walawend/TwilightLandscapes/DoF_article.shtml")
- "http://solo.colorado.edu/~walawend/TwilightLandscapes/DoF_article.shtml"))
+ ((:a :href "http://www.normankoren.com/Tutorials/MTF.html")
+ "http://www.normankoren.com/Tutorials/MTF.html"))
(:li
((:a :href "http://www.vanwalree.com/optics/dofderivation.html")
"http://www.vanwalree.com/optics/dofderivation.html"))