diff --git a/requirements.txt b/requirements.txt
index 30560a5..f001ee3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,22 +4,22 @@
 #
 #    pip-compile requirements.in
 #
-argparse==1.4.0
+argparse==1.4.0           # via -r requirements.in
 asn1crypto==0.24.0        # via cryptography
-cachecontrol==0.12.5
+cachecontrol==0.12.5      # via -r requirements.in
 certifi==2019.6.16        # via requests
 cffi==1.12.3              # via cryptography
 chardet==3.0.4            # via requests
 cryptography==2.7         # via pyopenssl
-feedparser==5.2.1
-html5lib==1.0.1
-httplib2==0.13.0
+feedparser==5.2.1         # via -r requirements.in
+html5lib==1.0.1           # via -r requirements.in
+httplib2==0.18.0          # via -r requirements.in
 idna==2.8                 # via requests
-lockfile==0.12.2
+lockfile==0.12.2          # via -r requirements.in
 msgpack==0.6.1            # via cachecontrol
 pycparser==2.19           # via cffi
-pyopenssl==19.0.0
-requests==2.22.0
+pyopenssl==19.0.0         # via -r requirements.in
+requests==2.22.0          # via -r requirements.in, cachecontrol
 six==1.12.0               # via cryptography, html5lib, pyopenssl
 urllib3==1.25.3           # via requests
 webencodings==0.5.1       # via html5lib