Hyundai don't publish them for free. Depending on the country you live in they may be available from your dealer but cost £100's. Cheap CD's on Ebay will at best probably be copies of information already freely available from the sites below.
The best sites to get this type of technical information for free, or little cost are:
www.hma-service.com (free, only covers USA cars and no Diesel) When using this site the information of interest is for the "Elantra Touring". You will need to register an account.
http://service.hyundai-motor.com/ (All European models, and U/U2 Diesel engines, some info free, some 5 Euros an hour to use)
You will need to register as an "Independant Repairer".