Add Accesibility recommendations

chapters/2.Accessibility_preservation.md

@@ -1,4 +1,32 @@
 # Accessibility and preservation 
 
 ## Objective
-To ensure accessibility and preservation, researchers and software engineers are strongly recommended to follow the archival and sharing recommendations below.
+To ensure accessibility and preservation, researchers and software engineers are strongly recommended to follow the archival and sharing recommendations below.
+
+## Recommendations
+### RSMD-2.1
+**Essential ☆☆☆**
+
+Archive the source code repository in the <span style="text-decoration:underline;">universal source code archive</span>, [Software Heritage](https://archive.softwareheritage.org/), using the [save code now,](save.softwareheritage.org) to ensure long-term access to the full development history. 
+
+* This method can be used for software at any level of maturity when software is publicly available. 
+
+### RSMD-2.2
+**Essential ☆☆☆**
+
+Archive software source code in a <span style="text-decoration:underline;">scholarly repository</span> (e.g [Zenodo](https://zenodo.org/), [HAL](https://hal.science/)) to ensure that software can be found and accessed in a _scholarly context_. 
+
+<span style="text-decoration:underline;">Note</span>: Proprietary software can be deposited in an institutional repository.
+
+* This method should be used when a software object is ready to be reported and shared. Some repositories offer the possibility to create a software record with the archived copy in RSMD-2.1 (e.g [HAL](https://www.softwareheritage.org/2023/04/04/swhid-deposit-hal/))
+
+
+
+### RSMD-2.3
+**Important ☆☆**
+
+Register software projects in a disciplinary or community registry (e.g [ascl.net](https://ascl.net/), [bio.tools](https://bio.tools/), [swMath](https://zbmath.org/software/), [RRID portal](https://scicrunch.org/resources/about/resource), [RSD](https://research-software-directory.org/),  [WikiData](https://www.wikidata.org/wiki/Wikidata:Main_Page), [DataCite](https://datacite.org/)) to ensure that software can be found and accessed. 
+
+To answer this recommendation, semi-automatic tools should be provided by infrastructures to reduce duplication of effort done by researchers or software creators.
+
+<span style="text-decoration:underline;">Note:</span> Proprietary software can be registered in an institutional catalog (e.g the INRIA BIL).