diff --git a/requirements.txt b/requirements.txt
index 10848ba..f9ca29d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,15 @@
 -i https://pypi.org/simple
+certifi==2019.6.16
+chardet==3.0.4
+idna==2.8
 iso-639==0.4.5
 numpy==1.17.0
 pandas==0.25.0
 python-dateutil==2.8.0
 python-stdnum==1.11
 pytz==2019.1
+requests-cache==0.5.0
+requests==2.22.0
 six==1.12.0
+urllib3==1.25.3
 xlrd==1.2.0