http://en.wikipedia.org/wiki/Digestion [2]
http://www.cfs.purdue.edu/class/f&n202/pdf_full/NL02-Digestion_and_absor... [3]
http://www.diet.com/g/digestion-and-absorption [4]
http://www.britannica.com/EBchecked/topic/1081754/human-digestive-system... [5]
https://www.boundless.com/biology/textbooks/boundless-biology-textbook/a... [6]
Links
[1] https://www.hootsgo.org/?q=node/6332
[2] http://en.wikipedia.org/wiki/Digestion
[3] http://www.cfs.purdue.edu/class/f&n202/pdf_full/NL02-Digestion_and_absorption.pdf
[4] http://www.diet.com/g/digestion-and-absorption
[5] http://www.britannica.com/EBchecked/topic/1081754/human-digestive-system/242920/Absorption
[6] https://www.boundless.com/biology/textbooks/boundless-biology-textbook/animal-nutrition-and-the-digestive-system-34/digestive-system-processes-197/digestion-and-absorption-754-11987/