@book{
  author = "太田, 達也",
  title = "ドイツ語",
  year: 2007
  month: 4
  key = "ドイツ語",
  publisher = "白水社",
  address = "東京",
  series = "ニューエクスプレス ;",
  ISSN/ISBN = "9784560066515 [4560066515]",
}