Put the flour in a deep container. Make a well and pour the eggs, yoghurt in which you've added and beaten the baking soda, the oil and salt. Stir everything, pour in 1/2 cup water as well. Knead well into a soft dough.
Sprinkle with flour and put in a glass bowl for about half an hour, covered with foil, in a warm area.
In the meantime, crumble the feta cheese and prepare a deep frying pan. Once 30 min. have passed, take the dough out of the bowl, divide it into 4 and roll out with a rolling pin. Put the feta cheese at one end and roll them up.
Once that's done, cut them every 8″ (20 cm), close the ends well, so the feta cheese doesn't spill out. Arrange them in a floured tray, to prevent them from sticking to one another.
Roll up the remaining 3 balls as well. Then fry them in the heated oil. You can serve with a sauce of your choice.