diff --git a/APCCM2017_Stanger.tex b/APCCM2017_Stanger.tex
index 40de508..68475d5 100644
--- a/APCCM2017_Stanger.tex
+++ b/APCCM2017_Stanger.tex
@@ -290,7 +290,7 @@
 
 \noindent The view update problem was first discussed in the relational context by Codd in 1974 \cite{Codd.E-1974a-Recent}. When an update operation is applied to a view, it needs to be translated into corresponding updates on the base relations from which the view is derived \cite{Keller.A-1985a-Algorithms}. Sometimes there are multiple translations that can produce the desired view update, but produce different---possibly incompatible---changes in the base relations. Worse, there may be translations that have side effects (e.g., for some views based on joins), which produce a different result in the view than if the updates were applied directly to an equivalent base relation \cite{Keller.A-1985a-Algorithms}. The problem then is how to choose the most appropriate translation. As yet there has been no solution that completely and automatically resolves this ambiguity.
 
-There has been considerable research into this problem over the last four decades, and numerous different approaches have been suggested. We shall now briefly review some key developments.
+There has been considerable research into this problem over the last four decades, and numerous different approaches have been suggested in the context of relational, non-relational (e.g., \cite{Liefke.H-2000a-View,Pan.W-1996a-Object}), and deductive databases (e.g., \cite{Behrend.A-2008a-Transformation-based,Caroprese.L-2012a-View-update,Console.L-1995a-Abduction}). We shall now briefly review some key developments in the relational context.
 
 Banchilhon and Spyratos proposed the concept of \emph{constant complement} \cite{Bancilhon.F-1981a-Update} in 1981. The \emph{complement} of a view describes all the information from the original database that does not appear in the view, so composing a view with its complement provides enough information to reconstruct the original database. Keeping the complement invariant under view update facilitates translation construction. This is a useful approach that has been developed further by other authors \cite{Hegner.S-2004a-Order-based,Lechtenborger.J-2003a-Impact}, but it has been shown that there are reasonable translations that cannot be carried out under constant complement \cite{Keller.A-1987a-Comment}. Computing the complement of a view is also difficult, and several authors have worked on more efficient algorithms \cite{Cosmadakis.S-1984a-Updates,Laurent.D-2001a-Monotonic,Lechtenborger.J-2003a-Computation}. Finally, this approach is purely structural in nature and does not consider the semantics of the schema, which is necessary to properly resolve translation ambiguity \cite{Keller.A-1986a-Role}.