@article(aitken98,
 author       = "J. S. Aitken and P. Gray and T. Melham and M. Thomas",
 year         = "1998",
 title        = "Interactive Theorem Proving: An Empirical Study of User Activity",
 journal      = "Journal of Symbolic Computation",
 volume       = "25",
 number       = "2",
 pages        = "263--284",
 doi          = "10.1006/jsco.1997.0175",
)
@article(aitken,
 author       = "J. Stuart Aitken and Thomas F. Melham",
 year         = "2000",
 title        = "An analysis of errors in interactive proof attempts",
 journal      = "Interacting with Computers",
 volume       = "12",
 number       = "6",
 pages        = "565--586",
 doi          = "10.1016/S0953-5438(99)00023-5",
)
@incollection(aitken95,
 author       = "Stuart Aitken and Philip Gray and Tom Melham and Muffy Thomas",
 year         = "1995",
 title        = "A Study Of User Activity In Interactive Theorem Proving",
 editor       = "Chris Johnson",
 booktitle    = "Task Centred Approaches To Interface Design: Glasgow Interactive Systems Group Research Review",
 publisher    = "Department of Computing Science, University of Glasgow",
 pages        = "195--218",
 note         = "GIST Technical Report G95.2",
)
@inproceedings(compare2012,
 author       = "Bernhard Beckert and Sarah Grebing",
 year         = "2012",
 title        = "Evaluating the Usability of Interactive Verification System",
 booktitle    = "Proceedings, 1st International Workshop on Comparative Empirical Evaluation of Reasoning Systems (COMPARE), Manchester, UK, June 30, 2012",
 series       = "CEUR Workshop Proceedings",
 volume       = "873",
 publisher    = "CEUR-WS.org",
 pages        = "3--17",
 url          = "http://ceur-ws.org/Vol-873",
)
@book(KeYBook2007,
 editor       = "Bernhard Beckert and Reiner H\"ahnle and Peter H. Schmitt",
 year         = "2007",
 title        = "Verification of Object-Oriented Software: The {KeY} Approach",
 series       = "LNCS 4334",
 publisher    = "Springer-Verlag",
 doi          = "10.1007/978-3-540-69061-0",
)
@misc(CDQuestionnaire,
 author       = "Alan Blackwell and Thomas R. Green",
 year         = "2007",
 title        = "A Cognitive Dimensions Questionnaire (Version 5.1.1)",
 howpublished = "{www.cl.cam.ac.uk/\~{}afb21/CognitiveDimensions/CDquestionnaire.pdf}",
)
@article(Caplan1990,
 author       = "Stanley Caplan",
 year         = "1990",
 title        = "Using focus group methodology for ergonomic design",
 journal      = "Ergonomics",
 volume       = "33",
 number       = "5",
 pages        = "527--533",
 doi          = "10.1080/00140139008927160",
 url          = "http://www.tandfonline.com/doi/abs/10.1080/00140139008927160",
)
@techreport(TPUsability,
 author       = "James Cheney",
 year         = "2001",
 title        = "Project Report -- Theorem Prover Usability",
 type         = "Technical Report",
 note         = "Report of project COMM 641, available at \url {http://homepages.inf.ed.ac.uk/jcheney/projects/tpusability.ps}",
)
@techreport(ParticipatoryMethodsToolkit,
 author       = "Janice Elliott and Sara Heesterbeek and Carolyn J. Lukensmeyer and Nikki Slocum",
 year         = "2005",
 title        = "{P}articipatory {M}ethods {T}oolkit: A practitioner's manual",
 type         = "Technical Report",
 institution  = "King Baudoin Foundation and Flemish Institute for Science and Technology Assessment (viWTA)",
)
@article(ProofCritics,
 author       = "Michael Jackson and Andrew Ireland and G. Reid",
 year         = "1999",
 title        = "Interactive Proof Critics",
 journal      = "Formal Aspects of Computing",
 volume       = "11",
 number       = "3",
 pages        = "302--325",
 doi          = "10.1007/s001650050052",
)
@inproceedings(kadodaDesirableFeatures,
 author       = "Gada Kadoda and Roger Stone and Dan Diaper",
 year         = "1996",
 title        = "Desirable Features of Educational Theorem Provers: A {Cognitive Dimensions} Viewpoint",
 booktitle    = "Proceedings of the 11th Annual Workshop of the Psychology of Programming Interest Group",
)
@incollection(ueq,
 author       = "Bettina Laugwitz and Theo Held and Martin Schrepp",
 year         = "2008",
 title        = "Construction and Evaluation of a User Experience Questionnaire",
 editor       = "Andreas Holzinger",
 booktitle    = "HCI and Usability for Education and Work",
 series       = "Lecture Notes in Computer Science",
 volume       = "5298",
 publisher    = "Springer Berlin Heidelberg",
 pages        = "63--76",
 doi          = "10.1007/978-3-540-89350-9\_6",
)
@book(Mayring2002,
 author       = "Philipp Mayring",
 year         = "1996",
 title        = "Einf\"uhrung in die qualitative Sozialforschung -- Eine Anleitung zu qualitativem Denken (Introduction to qualitative social research)",
 publisher    = "Weinheim: Psychologie Verlags Union",
)
@article(MayringOverview,
 author       = "Philipp Mayring",
 year         = "June 2000",
 title        = "Qualitative Content Analysis",
 journal      = "Forum: Qualitative Social Research",
 volume       = "1",
 number       = "2",
 note         = "Online Journal, 1(2). Available at: http://www.qualitative-research.net/index.php/fqs/article/view/1089 [Date of access: 08, 2014]",
)
@book(NielsenBook,
 author       = "Jakob Nielsen",
 year         = "1993",
 title        = "Usability Engineering",
 publisher    = "Morgan Kaufmann Publishers Inc.",
 address      = "San Francisco, CA, USA",
)
@book(Nipkow-Paulson-Wenzel:2002,
 author       = "Tobias Nipkow and Lawrence C. Paulson and Markus Wenzel",
 year         = "2002",
 title        = "Isabelle/HOL: A Proof Assistant for Higher-Order Logic",
 series       = "LNCS 2283",
 publisher    = "Springer",
 doi          = "10.1007/3-540-45949-9",
)
@book(UsabilityBook,
 author       = "Petra Vogt and Sven Heinsen",
 year         = "2003",
 title        = "Usability praktisch umsetzen: Handbuch f{\"{u}}r Software, Web, Mobile Devices und andere interaktive Produkte",
 publisher    = "Hanser",
)
@inproceedings(ImprovingFMTools,
 author       = "V. Vujosevic and G. Eleftherakis",
 year         = "2006",
 title        = "Improving Formal Methods' Tools Usability",
 editor       = "G. Eleftherakis",
 booktitle    = "2nd South-East European Workshop on Formal Methods (SEEFM 05), Formal Methods: Challenges in the Business World, Ohrid, 18-19 Nov 2005",
 publisher    = "South-East European Research Centre (SEERC)",
)