added reference to Stefan Hallerstede's proof obligation paper

git-svn-id: svn://svn.code.sf.net/p/rodin-b-sharp/svn/trunk/Handbook@15974 1434b563-b632-4741-aa49-43a3a8374d2e

org.rodinp.handbook.feature/latex/rodin-doc.tex

@@ -223,8 +223,13 @@ Those interested in more general guidelines on how to develop and structure form
 
 \subsection{Proofs for the Working Engineer (2008)}
 In his dissertation at the ETH Zurich Fahrad Mehta describes how theorem proving
-can be a practical tool for an engineer and presented the ideas that are used
-in building the fundament of Rodin.
+can be a practical tool for software engineers and presents the ideas that are used
+in building Rodin's infrastructure.
+
+\subsection{The Proof Obligation Generator (2005)}
+In this technical report (ETH Zürich)  Stefan Hallerstede describes which proof obligations
+(see Section~\ref{generated_proof_obligations}) are generated for a model
+and gives a justification why these are correct.
 
 \section{Conventions}
 \label{conventions}