Links
[1] https://hootsgo.org/?q=node/6350
[2] http://en.wikipedia.org/wiki/Osmoregulation
[3] http://www.biologyreference.com/Oc-Ph/Osmoregulation.html
[4] https://www.boundless.com/biology/textbooks/boundless-biology-textbook/osmotic-regulation-and-excretion-41/the-kidneys-and-osmoregulatory-organs-229/the-kidney-860-12107/