This letter of yours to me itself is a document demonstrating how great and a special person you are. You have made my life valuable and I felt honoured all my life as a result of your gesture in this document. It is framed and placed on the wall of my office since 1973 and will be there forever for sure. You were and still are a great advisor and more important friend not only during my thesis, after during my professional life as well. I am so fortunate to have you. Thank you, best regards.