@inproceedings{abney-light-1999-hiding,
    title = "Hiding a Semantic Hierarchy in a {M}arkov Model",
    author = "Abney, Steven  and
      Light, Marc",
    booktitle = "Unsupervised Learning in Natural Language Processing",
    year = "1999",
    url = "https://preview.aclanthology.org/Author-Pages-WenzhengZhang-ZhengyanShi-ShuYang/W99-0901/"
}