Matkovic is normally spelled the same, however some families added an "h" to the end
so that it would be properly pronounced with the ch sound as in Church, not the hard c sound as in
Spic n span. I'm not sure if Vucic and Vuksic are the same, but they are very close in spelling.
I have also seen vukelic, so there are some variations which I am uncertain of.
There is some interesting history about some email@example.com