You may simply send/write a letter to us:

Dr. Franjo Matejicek - MATING
Naselje Slavonija II 7/2
HR-35000 Slavonski Brod
CROATIA

You may dial phone
(during the day GSM): +385-91-132-61-91
(evening): +385-35-44-68-78,
You may send a fax on same number.

Maybe it is at simpliest to send e-mail.