Update readme with reference part

README.md

@@ -7,16 +7,20 @@ Ducque has four (4) main functions:
 - `--randomise` : returns a randomised sequence to the user.
 - `--gui` opens the GUI to use the modules up above, instead of the CLI. The `tlinker` module, in the `gui` module, is a specific preset for implementing linker fragments.
 
-## Documentation
+## Model building documentation
 A comprehensive manual of Ducque is found inside the `Ducque/docs/` directory !
 
 ## Forcefield
 To know more about how to build a forcefield, definitely check the `Ducque/ff/` directory!
 
 ### Charge derivation implementation with ORCA
 All scripts to calculate point charges, according to the AMBER-compatible MK population analysis scheme, can be found in the `Ducque/ff/scripts/` directory.
-<br>
+
 The `How_To_Create_A_Forcefield.pdf` file guides the user through the correct protocol and where to download the requires software packages.
 
+## Reference
+If you've used Ducque or any of its parts, or you've used the `How_To_Create_A_Forcefield.pdf` as a guide for your own research, please cite the following published article : 
+
+[1] Jérôme Rihon, Charles-Alexandre Mattelaer, Rinaldo Wander Montalvão, Mathy Froeyen, Vitor Bernardes Pinheiro, Eveline Lescrinier, Structural insights into the morpholino nucleic acid/RNA duplex using the new XNA builder Ducque in a molecular modeling pipeline, Nucleic Acids Research, 2024; DOI: 10.1093/nar/gkae135, [https://doi.org/10.1093/nar/gkae135](https://doi.org/10.1093/nar/gkae135)
 ## Authors
 Jérôme Rihon ([@jrihon](https://www.github.com/jrihon) )