Describe RIS baseline creation

Datasets/README.md

@@ -18,6 +18,15 @@ Below, you can find the baseline files which should represent the file as close
 | TSV | [_baseline.tsv](TSV/_baseline.tsv) |
 | XLSX | [_baseline.xlsx](XLSX/_baseline.xlsx) |
 
+The files were collected from [Lens.org](https://link.lens.org/cpUG60v0The) into a collection. This collection was then exported. Unfortunately, some of the the [export features for Lens.org are broken](https://twitter.com/TheLensOrg/status/1412911995930611713), so we decided to comprise the baseline files manually from the exported files from Lens.org.
+
+* First, the RIS file was uploaded;
+* second,[the obvious encoding errors were fixed](https://github.com/asreview/citation-file-formatting/commit/fc27c7946244112a01033411a5c473579a208dc9), namely the "�" was replaced with proper symbols;
+* third, [some numerical encoding errors were fixed](https://github.com/asreview/citation-file-formatting/commit/974e69398ffdad0a65ebb5ed56cb27f39ff18af9);
+* fourth, [fixed some additional missing encoding](https://github.com/asreview/citation-file-formatting/commit/d58228217bee0305ac2345082c127a4ff48be870), namely the "?" was replaced with proper symbols where needed;
+* additionally, we had to [add a "S" to secure a URL](https://github.com/asreview/citation-file-formatting/commit/72b81f0395d79f39b0c0fab316a00318d33af123) which was done properly in CSV but not in RIS.
+* as a bonus, some links are missing from the RIS that were initially present in the CSV.
+
 ## Exporting
 Below, you can find a list of files which have been exported from a specific tool or software *(e.g **[asreview.csv](CSV/asreview.csv)** represents a CSV which has been exported from ASReview)*.