README update

Author: Eugene Baulin

README.md

@@ -1,2 +1,16 @@
 # urslib2
-Library for processing RNA structures using PDB, DSSR and other data
+Library for processing RNA structures using PDB, DSSR and other data.
+
+# description
+
+urslib2 is an implementation of definitions of the RNA secondary structure elements described in:
+
+[Baulin, E., Yacovlev, V., Khachko, D., Spirin, S., & Roytberg, M. (2016). URS DataBase: universe of RNA structures and their motifs. Database, 2016.. DOI: 10.1093/database/baw085](https://doi.org/10.1093/database/baw085)
+
+urslib2 was used for the annotation of RNA long-range nucleotide doublets, see:
+
+[D.R. Bohdan, V.V. Voronina, J.M. Bujnicki, E.F. Baulin (2022) A comprehensive survey of long-range tertiary interactions and motifs in non-coding RNA structures. bioRxiv. DOI: 10.1101/2022.11.01.514747](https://doi.org/10.1101/2022.11.01.514747)
+
+The previous version of the library named "urslib" was used for the classification of RNA A-minor motifs, see:
+
+[Shalybkova, A. A., Mikhailova, D. S., Kulakovskiy, I. V., Fakhranurova, L. I., & Baulin, E. F. (2021). Annotation of the local context of RNA secondary structure improves the classification and prediction of A-minors. RNA, 27(8), 907-919.. DOI: 10.1261/rna.078535.120](https://doi.org/10.1261/rna.078535.120)