diff --git a/requirements.txt b/requirements.txt
index 6781945..96abf08 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
-lxml
-bs4
-selenium
+lxml>=4.0.0
+bs4>=0.0.1
+selenium>=3.0.0
+networkx>=2.0.0