With Otto Frank's death in 1980, the original diary, including letters and loose sheets, was willed to the Dutch Institute for War Documentation, which commissioned a forensic study of the diary through the Netherlands Ministry of Justice in 1986. They examined the handwriting against known examples and found that they matched. They determined that the paper, glue, and ink were readily available during the time the diary was said to have been written. They concluded that the diary is authentic, and their findings were published in what has become known as the "Critical Edition" of the diary. In 1990, the Hamburg Regional Court confirmed the diary's authenticity.