Per anno

 @incollection{ctxlp-elpIII,
    acm = {736334},
    author = {Denti, Enrico and Lamma, Evelina and Mello, Paola and Natali, Antonio and Omicini, Andrea},
    booktitle = {Extensions of Logic Programming},
    dblp = {conf/elp/DentiLMNO92},
    doi = {10.1007/3-540-56454-3_17},
    editor = {Lamma, Evelina and Mello, Paola},
    eisbn = {978-3-540-47562-0},
    isbn = {978-3-540-56454-6},
    isbn-10 = {3-540-56454-3},
    isbn10 = {3-540-56454-3},
    issn = {0302-9743},
    keywords = {Virtual Machine, Logic Program, Logic Programming, Hypothetical Reasoning, Program Clause},
    note = {3rd International Workshop (ELP'92), Bologna, Italy, 26--28~} # feb # {~1992. Proceedings},
    pages = {339--358},
    publisher = {Springer},
    scopus = {2-s2.0-85028860344},
    series = {Lecture Notes in Computer Science},
    subseries = {Lecture Notes in Artificial Intelligence},
    title = {Techniques for Implementing Contexts in {L}ogic {P}rogramming},
    url = {http://link.springer.com/10.1007/3-540-56454-3_17},
    volume = 660,
    year = 1993
} 

 @incollection{oolp-plilp93,
    acm = {692617},
    author = {Natali, Antonio and Omicini, Andrea},
    booktitle = {Programming Language Implementation and Logic Programming},
    dblp = {conf/plilp/NataliO93},
    doi = {10.1007/3-540-57186-8_81},
    editor = {Bruynooghe, Maurice and Penjam, Jaan},
    eisbn = {978-3-540-47945-1},
    isbn = {978-3-540-57186-5},
    isbn-10 = {978-3-540-57186-5},
    isbn10 = {3-540-57186-8},
    issn = {0302-9743},
    note = {5th International Symposium (PLILP'93), Tallinn, Estonia, 25--27~} # aug # {~1993. Proceedings},
    pages = {220--234},
    publisher = {Springer-Verlag},
    scopus = {2-s2.0-21144462602},
    series = {Lecture Notes in Computer Science},
    title = {Objects with State in {C}ontextual {L}ogic {P}rogramming},
    url = {http://link.springer.com/10.1007/3-540-57186-8_81},
    volume = 714,
    year = 1993
} 

 @inproceedings{lprobot-gulp93,
    address = {Gizzeria Lido, CZ, Italy},
    author = {Natali, Antonio and Omicini, Andrea and Zanichelli, Francesco},
    booktitle = {8th Italian Conference on Logic Programming (GULP'93)},
    dblp = {conf/agp/NataliOZ93},
    editor = {Saccà, Domenico},
    month = {15--18}}},
    title = {Exploiting {L}ogic {P}rogramming in Robot Applications},
    year = 1993
}