add link to paper

README.md

@@ -27,6 +27,12 @@ cd mpib_sp_eeg
 datalad get participants.tsv
 ```
 
+## Paper
+
+The paper is available (open access) in Cerebral Cortex.
+
+- Cerebral Cortex: https://doi.org/10.1093/cercor/bhac062
+
 ## Preprint
 
 A preprint is available on BioRxiv.