Such a division is used in Eesti nõukogude entsüklopeedia, 2. kd, as well as by Mari MustOn Eastern Viru languages(in Estonian). Other sources may group the coastal dialects as subdivision of Northern Estonian dialects or just as one of the dialect groups of the Estonian language, without a binary division into Northern and Southern Estonian ([1], [2])
galerii.ee
Such a division is used in Eesti nõukogude entsüklopeedia, 2. kd, as well as by Mari MustOn Eastern Viru languages(in Estonian). Other sources may group the coastal dialects as subdivision of Northern Estonian dialects or just as one of the dialect groups of the Estonian language, without a binary division into Northern and Southern Estonian ([1], [2])