diff --git a/common/modules/swh-scientific-preservation.org b/common/modules/swh-scientific-preservation.org
index dd97d44..2c34b13 100644
--- a/common/modules/swh-scientific-preservation.org
+++ b/common/modules/swh-scientific-preservation.org
@@ -1,95 +1,95 @@
 #+COLUMNS: %40ITEM %10BEAMER_env(Env) %9BEAMER_envargs(Env Args) %10BEAMER_act(Act) %4BEAMER_col(Col) %10BEAMER_extra(Extra) %8BEAMER_opt(Opt)
 #+INCLUDE: "prelude.org" :minlevel 1
 * Software Heritage for Scientific Publishing
   :PROPERTIES:
   :CUSTOM_ID: main
   :END:
 ** Save and reference research software \hfill \href{https://www.softwareheritage.org/save-and-reference-research-software/}{SWH guidelines}
   :PROPERTIES:
   :CUSTOM_ID: prepare
   :END:
 *** Prepare your public repository with: :B_picblock:
     - README, LICENSE, AUTHORS & codemeta.json files
 #+LATEX: \pause
 
 *** What's a good README
 \hfill extracted from \href{https://www.tldp.org/HOWTO/html_single/Software-Release-Practice-HOWTO/}{Eric Steven Raymond} and
 \href{https://www.makeareadme.com/}{Make a README}
 
-   /MUST/ include:
+  /MUST/ include:
       - **Name** and a **description** of the software.
   #+BEAMER: \pause
   /SHOULD/ include:
       - how to **run** and **use** the source code
       - build **environment**, installation, requirements
  #+BEAMER: \pause
   /CAN/ include:
       - project **website** or **documentation** pointer and recent **news**
       - **visuals**
 
 
 
 ** Save and reference research software  \hfill \href{https://www.softwareheritage.org/save-and-reference-research-software/}{SWH guidelines}
 :PROPERTIES:
 :CUSTOM_ID: save
 :END:
 *** Save code now on \hfill \url{https://archive.softwareheritage.org/save/}
     - git, svn or mercurial
     - intrinsic metadata files
     - complete history
 
 
 #+latex: \begin{center}
 #+ATTR_LATEX: :width \linewidth
 file:webui-save-code-now.png
 #+latex: \end{center}
 
 ** Save and reference research software  \hfill \href{https://www.softwareheritage.org/save-and-reference-research-software/}{SWH guidelines}
 :PROPERTIES:
 :CUSTOM_ID: reference
 :END:
   Choose the granularity level for the reference:
 
   #+BEAMER: \pause
 *** file (with code fragment)
   #+BEGIN_EXPORT latex
   \begin{tcolorbox}
   \href{https://archive.softwareheritage.org/swh:1:cnt:c60366bc03936eede6509b23307321faf1035e23;lines=473-537;origin=https://github.com/sagemath/sage/}
   {swh:1:{\bf cnt}:c60366bc03936eede6509b23307321faf1035e23;lines=473-537}\\
   \mbox{} \hfill ... and add {\it ;origin=https://github.com/sagemath/sage/}
   \end{tcolorbox}
   \hfill James McCaffrey's {\bf algorithm} in sageMath
   #+END_EXPORT  
   #+BEAMER: \pause
 *** directory 
   #+BEGIN_EXPORT latex
   \begin{tcolorbox}
   \href{https://archive.softwareheritage.org/swh:1:dir:c6f07c2173a458d098de45d4c459a8f1916d900f;origin=https://github.com/id-Software/Quake-III-Arena/}
   {swh:1:{\bf dir}:c6f07c2173a458d098de45d4c459a8f1916d900f}\\
   \mbox{}\hfill ... and add {\it ;origin=https://github.com/id-Software/Quake-III-Arena/}
   \end{tcolorbox}
   \hfill source code of {\bf Quake-III Arena} from id-Software
   #+END_EXPORT  
 ** Save and reference research software  \hfill \href{https://www.softwareheritage.org/save-and-reference-research-software/}{SWH guidelines}
 :PROPERTIES:
 :CUSTOM_ID: referencecontd
 :END:
 *** specific release
   #+BEGIN_EXPORT latex
   \begin{tcolorbox}
   \href{https://archive.softwareheritage.org/swh:1:rel:22ece559cc7cc2364edc5e5593d63ae8bd229f9f;origin=https://github.com/darktable-org/darktable/}
   {swh:1:{\bf rel}:22ece559cc7cc2364edc5e5593d63ae8bd229f9f}\\
   \mbox{}\hfill ... and add {\it ;origin=https://github.com/darktable-org/darktable/}
   \end{tcolorbox}
   \hfill {\bf release} 2.3.0 of Darktable, dated 24 December 2016
   #+END_EXPORT  
   #+BEAMER: \pause
 *** full snapshot (including all branches and all releases) 
   #+BEGIN_EXPORT latex
   \begin{tcolorbox}
   \href{https://archive.softwareheritage.org/swh:1:snp:c7c108084bc0bf3d81436bf980b46e98bd338453;origin=https://github.com/darktable-org/darktable/}
   {swh:1:{\bf snp}:c7c108084bc0bf3d81436bf980b46e98bd338453}\\
   \mbox{}\hfill ... and add {\it ;origin=https://github.com/darktable-org/darktable/}
   \end{tcolorbox}
   \hfill a {\bf snapshot} of the entire Darktable repository (4 May 2017, GitHub)
   #+END_EXPORT