- "http://www.vanwalree.com/optics/dofderivation.html")
- ((:a :href "http://www.photo.net/learn/optics/lensFAQ")
- "http://www.photo.net/learn/optics/lensFAQ")
- ((:a :href "http://www.mhohner.de/formulas.php")
- "http://www.mhohner.de/formulas.php")
- )
+ "http://www.vanwalree.com/optics/dofderivation.html"))
+ (:li ((:a :href "http://www.photo.net/learn/optics/lensFAQ")
+ "http://www.photo.net/learn/optics/lensFAQ"))
+ (:li ((:a :href "http://www.mhohner.de/formulas.php")
+ "http://www.mhohner.de/formulas.php"))