@Misc{alti:ott-conf,
  author =	 {Thorsten Altenkirch and Conor McBride},
  title =	 {Towards Observational Type Theory},
  howpublished = {Manuscript, available online},
  month =	 {February},
  year =	 {2006}
}

@inproceedings{alti:ott-conf,
 author = {Thorsten Altenkirch and Conor McBride and Wouter Swierstra},
 title = {Observational equality, now!},
 booktitle = {PLPV '07: Proceedings of the 2007 workshop on Programming languages meets program verification},
 year = {2007},
 isbn = {978-1-59593-677-6},
 pages = {57--68},
 location = {Freiburg, Germany},
 doi = {http://doi.acm.org/10.1145/1292597.1292608},
 publisher = {ACM},
 address = {New York, NY, USA},
 }