P. Ehlen, и M. Johnston. Proceedings of the 16th international conference on Intelligent user interfaces, стр. 435--436. New York, NY, USA, ACM, (2011)
P. Ehlen, M. Johnston, и G. Vasireddy. Proceedings of ICSLP---Interspeech 2002: 7th International Conference on Spoken Language Processing, Denver, CO, USA, стр. 2557-2560. (2002)
P. Ehlen, M. Purver, и J. Niekrasz. Interaction Challenges for Intelligent Assistants, том SS-07-04 из AAAI Technical Report, стр. 33-40. AAAI Press, (2007)
P. Ehlen, R. Zajac, и K. Rao. Proceedings of the Second International Workshop on Location and the Web (LocWeb 2009), стр. 17-19. Boston, Massachusetts, (апреля 2009)