@inproceedings(Bezem99,
 author       = {Marc Bezem},
 year         = {1999},
 title        = {Extensionality of Simply Typed Logic Programs},
 editor       = {Danny De Schreye},
 booktitle    = {Logic Programming: The 1999 International Conference, Las Cruces, New Mexico, USA, November 29 - December 4, 1999},
 publisher    = {{MIT} Press},
 pages        = {395--410},
)
@inproceedings(Bezem01,
 author       = {Marc Bezem},
 year         = {2001},
 title        = {An Improved Extensionality Criterion for Higher-Order Logic Programs},
 editor       = {Laurent Fribourg},
 booktitle    = {Computer Science Logic, 15th International Workshop, {CSL} 2001. 10th Annual Conference of the EACSL, Paris, France, September 10-13, 2001, Proceedings},
 series       = {Lecture Notes in Computer Science},
 volume       = {2142},
 publisher    = {Springer},
 pages        = {203--216},
 doi          = {10.1007/3-540-44802-0\_15},
)
@inproceedings(Bezem2002,
 author       = {Marc Bezem},
 year         = {2002},
 title        = {Hoapata programs are monotonic},
 booktitle    = {Proceedings NWPT’02, Institute of Cybernetics at TTU, Tallinn},
 pages        = {18--20},
)
@article(CharalambidisER14,
 author       = {Angelos Charalambidis and Zolt{\'{a}}n {\'{E}}sik and Panos Rondogiannis},
 year         = {2014},
 title        = {Minimum Model Semantics for Extensional Higher-order Logic Programming with Negation},
 journal      = {{TPLP}},
 volume       = {14},
 number       = {4-5},
 pages        = {725--737},
 doi          = {10.1017/S1471068414000313},
)
@article(CharalambidisHRW13,
 author       = {Angelos Charalambidis and Konstantinos Handjopoulos and Panagiotis Rondogiannis and William W. Wadge},
 year         = {2013},
 title        = {Extensional Higher-Order Logic Programming},
 journal      = {{ACM} Trans. Comput. Log.},
 volume       = {14},
 number       = {3},
 pages        = {21},
 doi          = {10.1145/2499937.2499942},
)
@article(CKW93-187,
 author       = {Weidong Chen and Michael Kifer and David Scott Warren},
 year         = {1993},
 title        = {{HILOG:} {A} Foundation for Higher-Order Logic Programming},
 journal      = {Journal of Logic Programming},
 volume       = {15},
 number       = {3},
 pages        = {187--230},
 doi          = {10.1016/0743-1066(93)90039-J},
)
@inproceedings(KRW05,
 author       = {Vassilis Kountouriotis and Panos Rondogiannis and William W. Wadge},
 year         = {2005},
 title        = {Extensional Higher-Order Datalog},
 booktitle    = {Short Paper Proceeding of the 12th International Conference on Logic for Programming, Artificial Intelligence and Reasoning (LPAR)},
 pages        = {1--5},
)
@book(lloyd,
 author       = {John W. Lloyd},
 year         = {1987},
 title        = {Foundations of Logic Programming},
 publisher    = {Springer Verlag},
 doi          = {10.1007/978-3-642-83189-8},
)
@book(MN2012,
 author       = {Dale Miller and Gopalan Nadathur},
 year         = {2012},
 title        = {Programming with Higher-Order Logic},
 edition      = {1st},
 publisher    = {Cambridge University Press},
 address      = {New York, NY, USA},
 doi          = {10.1017/CBO9781139021326},
)
@inproceedings(Wa91a,
 author       = {William W. Wadge},
 year         = {1991},
 title        = {Higher-Order Horn Logic Programming},
 editor       = {Vijay A. Saraswat and Kazunori Ueda},
 booktitle    = {Logic Programming, Proceedings of the 1991 International Symposium, San Diego, California, USA, Oct. 28 - Nov 1, 1991},
 publisher    = {{MIT} Press},
 pages        = {289--303},
)