Фоторецептор — разлика између измена

* {{Cite book|ref=harv|last=Campbell|first= Neil A.,|last2=Reece|first2= Jane B. |title=Biology |publisher=Benjamin Cummings |location=San Francisco |year=2002 |id=ISBN 978-0-8053-6624-52|pages=1064-1067 }}

* {{Cite book|ref=harv|last=Freeman|first=Scott|title=Biological Science (2nd Edition) |publisher=Prentice Hall |location=Englewood Cliffs, N.J |year=2002 |id=ISBN 978-0-13-140941-75|pages=835-837 }}