According to information from over here the family was from the village of Jasikovac, Korenica, Croatia. Some records of Serbian Orthodox Church from Croatia are available online via familysearch but I have to check what is there and which parish you need - in any case these will most probably be earlier records.

If the family is still Serbian Orthodox or if Dane remained member of the SOC after emigrating try to locate any marriage records, baptism records of his children and even his children's marriage records - and you need to hunt down and make copies of the original records - often in them the exact village of origin and household number was written for the people who emigrated. This will help you find people who are descendants of the same branch who can help fill in the gaps or obtain records locally.

I will also browse the WWII victims of genocide records, since families over there suffered great losses.

If you find any census or draft or immigration record that has a middle name in it, that will be the first name of his father.

For more tips on how to research check out this research article :

http://www.rodoslovlje.com/documentation/guide-researching-ethnic-serbian-ancestors-austria-hungary

and for some insights into community and history of Serbs from Korenica you can visit this heritage web site :

http://korenicani.com/starefotke.htm