This recipe is from a clipping out of an old magazine and came from an unnamed restaurant in Sofia, Bulgaria. Sarma is similar to Turkish dolma since this type of food dates from the days of the Ottoman Empire.
There are different versions of this recipe from all over the Balkans. You may be able to get sour cabbage from an Eastern European market; if not, you can boil the cabbage heads until soft enough to work with (the dish will taste slightly different – maybe add some vinegar to the broth). It is a very filling dish! Don’t worry about leftovers, they taste just fine reheated (use the stove, not the microwave)!