Greetings,
Finally, I am thinking using an other EHR for my project, more suitable for what I want to do. Ofcourse, I will make an extended reference of openEHR in my Master thesis, as I have learned many things about it. In my opinion, it's a mature project, with many years of research in the field of e-Health and I think shows the way how a modern EHR should be structured. It's a huge project and plenty of time should be devoted on it.
Thank you everyone for your help!
Panagiotis.