+% \lambda\delta version 3 (proposed) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+@misc{lambdadeltaJ3a,
+ author="F. {Guidi}",
+ title="{Verified Representations of Landau's ``Grundlagen'' in $\lambda\delta$ and in the Calculus of Constructions}",
+ year="2015",
+ month="August",
+ note="Submitted to JFR, University of Bologna (available at $<$\url{http://lambdadelta.info/}$>$)"
+}
+
+% \lambda\delta version 2 (active) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+@comment{lambdadeltaJ2a,
+ author="F. {Guidi}",
+ title="{The Formal System $\lambda\delta$ Revised: Extending the Applicability Condition}",
+ howpublished="CoRR identifier 1411.0154",
+ year="2014",
+ month="November",
+ note="Preprint (available at $<$\url{http://lambdadelta.info/}$>$)"
+}
+
+@techreport{lambdadeltaR2c,
+ author="F. {Guidi}",
+ title="{Extending the Applicability Condition in the Formal System $\lambda\delta$}",
+ type="Technical Report",
+ number="AMS Acta 4411",
+ institution="University of Bologna",
+ address="Bologna, Italy",
+ year="2015",
+ month="December"
+}
+
+@misc{lambdadeltaV2a,
+ author="F. {Guidi}",
+ title="{lambdadelta\_2A1}",
+ howpublished="Formal specification for the proof assistant Matita 0.99.2",
+ year="2014",
+ month="October",
+ note="Available at $\lambda\delta$ Web site: $<$\url{http://lambdadelta.info/}$>$"
+}
+
+@incollection{lambdadeltaR2b,