I live in South Carolina, but I was born and raised in Risan, Montenegro, which is right down the road from Kostanjica. My immediate family still lives in Risan. I was just wondering if you have had any luck finding the birth certificate of your grandfather. I may be able to help you a little bit. A friend of mine lives in Kostanjica. Her last name is Dabovic (her married name). If you would like, I can ask her if she has info on Mr. Martin Anton Dabovic...Just let me know...