diff --git a/README.txt b/README.txt
index fd5544b930a9456016ed00e7bf17eb8b136fb517..162d849e2b6aa7675a7eb1c536cfae1629b7a239 100644
--- a/README.txt
+++ b/README.txt
@@ -7,3 +7,5 @@ Type make to build the program named treedepth. Type ./treedepth -help to print
 For example ./treedepth -file heur_111.gr time 60.
 Use make PACE=yes to generate a version of the program corresponding to pace 2020 requirements (no options in line then).
 
+DOI 10.5281/zenodo.3884054
+