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\newblock {\em ACM Computing Surveys}, 12(4):525--565, December 1987.

\bibitem{AH88}
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\newblock Restructuring hierarchical database objects.
\newblock {\em Theoretical Computer Science}, 1988.

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\newblock Frames as terms and types ({Initial Investigations}).
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\newblock On the epistemological status of semantic networks.
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\newblock {KRYPTON}: A functional approach to knowledge representation.
\newblock {\em IEEE Computer}, 16(11), 1983.

\bibitem{BS85}
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\newblock An overview of the {KL-ONE} knowledge representation system.
\newblock {\em Cognitive Science}, 9(2), 1985.

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\newblock {\em Journal of the ACM}, 27(4), 1980.

\bibitem{HK87}
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\newblock Semantic database modeling: Survey, applications and research issues.
\newblock {\em ACM Computing Surveys}, 19(3), September 1987.

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\newblock Springer LNAI, New York, Berlin, 1990.

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\newblock Hybrid reasoning in {BACK}.
\newblock In {\em Proc. of ISMIS-88}. Elsevier, 1988.

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