I am looking for some help finding ANY information on the uniform in these pictures. The man seated on the far left we believe is my 3rd great grandfather (some family members believe it is his son John Petrovich). He was called Papa but we don't know his first name, his last name is Petrovich. His oldest son (John) was born in 1882 and per his naturalization papers was born in Lelo Ljuba, Now Jugoslavia, Austria and came to the united states in 1910. John lists himself as Austrian speaking Croatian so I assume his father would be the same. Based on his age I believe that his father (pictured) would have been military age at about 1880ish? I believe that they are Austro-Hungarian but I am not sure and I can't seem to make a match. The knots on the sleeves are different from other uniforms. I have looked into the insignia's on the hats (from the shape) don't match anything I've seen either. The photo is marked in the bottom left and the photographer Stefan Ossko, who was a photographer in Saravejo, Bosnia and Herzegovina in the late 19th century. Please let me know if you have any information that will help me in my research.