diff --git a/examples/scholarly_paper/2021-ITP-PMTI/document/root.bib b/examples/scholarly_paper/2021-ITP-PMTI/document/root.bib
index 445dbed1..3f5e5480 100644
--- a/examples/scholarly_paper/2021-ITP-PMTI/document/root.bib
+++ b/examples/scholarly_paper/2021-ITP-PMTI/document/root.bib
@@ -20,6 +20,7 @@
   note		= {Part of the Isabelle distribution.}
 }
 
+
 @TechReport{	  bsi:50128:2014,
   type		= {Standard},
   key		= {BS EN 50128:2011},
@@ -55,6 +56,15 @@
 		  the development, deployment and maintenanceactivities.}
 }
 
+@inproceedings{naraschewski1998object,
+  title={Object-oriented verification based on record subtyping in higher-order logic},
+  author={Naraschewski, Wolfgang and Wenzel, Markus},
+  booktitle={International Conference on Theorem Proving in Higher Order Logics},
+  pages={349--366},
+  year={1998},
+  organization={Springer}
+}
+
 @InCollection{	  brucker.ea:isabelledof:2019,
   abstract	= {DOF is a novel framework for defining ontologies and
 		  enforcing them during document development and evolution. A
diff --git a/examples/scholarly_paper/2021-ITP-PMTI/paper.thy b/examples/scholarly_paper/2021-ITP-PMTI/paper.thy
index b12c0f3f..0992ada9 100644
--- a/examples/scholarly_paper/2021-ITP-PMTI/paper.thy
+++ b/examples/scholarly_paper/2021-ITP-PMTI/paper.thy
@@ -378,10 +378,44 @@ text\<open>\<^dof>'s generated antiquotations are part of a general mechanism of
 \<close>
 
 *)
+(*<*)
+type_synonym A = int 
+type_synonym B = int
+record T =
+  x :: A
+  y :: B
+(*>*)
+
+term "\<lparr>x = a,y = b\<rparr>"
 
 subsection\<open>Meta-Objects as Extensible Records\<close>
+(* too fat ? what do we need of this ? *)
+text\<open>
+Isabelle/HOL supports both fixed and schematic records at the level of terms and 
+types. The notation for terms and types is as follows:
 
-text\<open>Explain record notation.\<close>
+\<^item> fixed record terms     \<^term>\<open>\<lparr>x = a,y = b\<rparr>\<close>; fixed record types \<open>\<lparr>x::A, y::B\<rparr>\<close>.
+\<^item> schematic record terms \<^term>\<open>\<lparr>x = a,y = b, \<dots> = m::'a\<rparr>\<close>; 
+  schematic record types: \<open>\<lparr>x::A, y::B, \<dots> = 'a\<rparr>\<close> which were usually abbreviated
+  to \<^typ>\<open>'a T_scheme\<close>.
+\<^item> selectors are written \<^term>\<open>x(R::'a T_scheme)\<close>, \<^term>\<open>y(R::'a T_scheme)\<close>. 
+\<^item> updates were denoted \<^term>\<open>r\<lparr>x := a\<rparr>\<lparr>y := b\<rparr>\<close> or just \<^term>\<open>r\<lparr>x:=a, y:=b\<rparr>\<close>. 
+\<close>
+
+text\<open> ... where the so-called more-field \<open>\<dots>\<close> is used to 'fill-in' record-extensions.
+Schematic record types allow for simulating object-oriented features such as 
+(single-)inheritance while maintaining a compositional style of verification
+@{cite "naraschewski1998object"}: it is possible to prove a property \<^term>\<open>P (x::'a T\<close>
+which will remain true for all extensions (which are just instances of the
+\<^typ>\<open>'a T\<close>-type). 
+\<close>
+
+text\<open>In \<^dof>, \<^verbatim>\<open>onto_class\<close>es and the logically equivalent  \<^verbatim>\<open>doc_class\<close>es were
+represented by schematic record types and instances thereof by schematic terms. 
+Invariants of an \<^verbatim>\<open>onto_class\<close> are thu predicates over schematic record
+types and can therefore be inherited in a subclass. \<^dof> handles the parametric  
+polymorphism implicitly. 
+\<close>
 
 subsection\<open>Code-Generation in Isabelle\<close>