diff --git a/.travis.yml b/.travis.yml
index 24687b97..5e032609 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,8 @@ sudo: false
 addons:
   apt:
     packages:
+    - zlib1g-dev
+    - libgmp3-dev
     - gfortran
     - gcc
     - liblapack-dev
diff --git a/doc/source/conf.py b/doc/source/conf.py
index c77267ea..e461323a 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -25,7 +25,7 @@ import sys, os
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinx.ext.autodoc', 'sphinx.ext.doctest', 'sphinx.ext.todo', 'sphinx.ext.pngmath', 'sphinx.ext.mathjax', 'sphinx.ext.viewcode']
+extensions = ['sphinx.ext.autodoc', 'sphinx.ext.doctest', 'sphinx.ext.todo', 'sphinx.ext.mathjax', 'sphinx.ext.viewcode']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
diff --git a/install/scripts/install_ocaml.sh b/install/scripts/install_ocaml.sh
index a7462b2e..913ae75d 100755
--- a/install/scripts/install_ocaml.sh
+++ b/install/scripts/install_ocaml.sh
@@ -5,7 +5,7 @@ QP_ROOT=$PWD
 cd -
 
 # Normal installation
-PACKAGES="core cryptokit ocamlfind sexplib ZMQ"
+PACKAGES="core cryptokit zarith ocamlfind sexplib ZMQ"
 #ppx_sexp_conv
 
 # Needed for ZeroMQ