http://en.wikipedia.org/wiki/Alveolar-arterial_gradient

http://www-users.med.cornell.edu/~spon/picu/calc/aagrad.htm

http://www.globalrph.com/aagradient.htm

http://www.drgenie.com/Procedures/aaa/a1.html

http://www.funadvice.com/q/what_is_the_alveolar_arterial_gradient

http://www.pediatriconcall.com/fordoctor/pedcalc/a_a_Gradient.asp

http://www.madsci.com/manu/gas_aa.htm

http://www.lakesidepress.com/pulmonary/ABG/PO2.htm

http://emergencymedic.blogspot.com/2009/01/alveolar-arterial-partial-pressure.html

http://www.ncbi.nlm.nih.gov/pubmed/9500505

http://en.wikipedia.org/wiki/Alveolar_gas_equation

http://www.uptodate.com/patients/content/topic.do?topicKey=~3l342uVi8wnnC

http://www.perinatology.com/calculators/A-a%20gradient.htm

http://biomed.gerontologyjournals.org/cgi/content/full/55/12/M761

http://cmbi.bjmu.edu.cn/uptodate/critical%20care/Monitoring/Interpretation%20of%20arterial%20oxygen%20tension.htm

http://cat.inist.fr/?aModele=afficheN&cpsidt=2173262

http://www.globalrph.com/martin_4_most2.htm

http://ncemi.asatte.org/etools_c/about_files/edcalc_0room_air_alveolar-arterial_gradient.xml.htm

http://www.gpnotebook.co.uk/xda.cfm?ID=436600836

http://www.fpnotebook.com/Renal/Lab/AGrdnt.htm