@inproceedings(1991-on-the-structure-of-subword-units-for-a-speker-independent-continuous-speech-task,
  author = {Emilio Sanchis Arnal},
  title = {On the Structure of Subword units for a Speker Independent Continuous Speech task},
  year = {1991},
  booktitle = {European Conference on Speech Communication and Technology (EUROSPEECH)},
  address = {Genova, Italia},
  pages = {675-678}
)