diff --git a/Project.toml b/Project.toml
index c3b08cb..ceba26c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -31,6 +31,7 @@ GeometricSolutions = "0.3"
 LaTeXStrings = "1"
 Parameters = "0.12, 0.13"
 Plots = "1"
+PoincareInvariants = "0.4"
 RecipesBase = "1"
 julia = "1.6"