adding DOIs to references

diff --git a/README b/README
index c5ddc5f..ce715dc 100644
--- a/README
+++ b/README
@@ -467,8 +467,11 @@ Publications where RACS has been used:
 - "The Med31 conserved component of the divergent Mediator complex in
   Tetrahymena thermophila participates in developmental regulation",
   Garg et al., Current Biology (2019) Vol 29(13).
+  https://doi.org/10.1016/j.cub.2019.06.052

 - "The bromodomain-containing protein Ibd1 links multiple chromatin-related
   protein complexes to highly expressed genes in Tetrahymena thermophila",
   Saettone et al, Epigenetics & Chromatin (2018) Vol 11(10).
+  https://doi.org/10.1186/s13072-018-0180-6
+