Yamagata-ken (Japan). Kikakubu. Tōkeika

• Yamagata-ken chingin kōzō kihon chōsa kekka hōkokuaho
• Yamagata-ken no jinkō to setaisū
• Yamagata-ken no kigyō rōdōsha no chingin, rōdō jikan oyobi koyō no ugoki