Here is some references you want:

http://journal.ashspublications.org/content/115/3/458.full.pdf

http://cdn.intechopen.com/pdfs/30581/InTech-Determination_of_the_chemical_composition_of_volatile_oils_of_plants_using_superheated_water_extraction_with_comprehensive_gas_chromatography_time_of_flight_mass_spectrometry.pdf

http://www.agriculturejournals.cz/publicFiles/84629.pdf

http://europepmc.org/abstract/MED/18656673/reload=0;jsessionid=RnMV17LNHSTHuf7pgZMd.38

http://ac.els-cdn.com/S1877705812028160/1-s2.0-S1877705812028160-main.pdf?_tid=e5ae5df8-4d47-11e3-bd9a-00000aacb360&acdnat=1384445874_d629731f9d742b7ba91ab6bdef331000

Good Luck

Here is another link of a good reference:

http://europepmc.org/abstract/MED/22595519

thanks for the good references Hossein