bo-bo bobov bobr bogor bogu bogur booru borbo borgo borgu boro- boroo borou borov borro borvo bourg brobo brrrr brugg bugoo burgo burgu buroo burov burro burru go-go go-oo gobbo gogro goobo gorgo gouv- grgur grogg grrrr grubb gubbo gubru guroo gurov gurro gurur o-r-b oboro obrov ogogo ogugu ooooo oovoo orgov orobo orrgo oruro ouoro ro-ro robbo robo- robor robur rogov rorbu rubor ubobo ugro- ugrug uroob urour urubu uuuuu uvrou v-bob v-bor voobu vooru vrbov