diff --git a/biosppy/storage.py b/biosppy/storage.py
index d1946099..99598a11 100644
--- a/biosppy/storage.py
+++ b/biosppy/storage.py
@@ -13,11 +13,11 @@
 # built-in
 import json
 import os
+import zipfile
 
 # 3rd party
 import h5py
 import shortuuid
-import zipfile
 from sklearn.externals import joblib
 
 # local
diff --git a/docs/conf.py b/docs/conf.py
index 6be172e9..d512f31b 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -16,6 +16,16 @@
 import os
 import shlex
 
+# To be able to import to ReadTheDocs
+import mock
+ 
+MOCK_MODULES = ['numpy', 'scipy', 'matplotlib', 'matplotlib.pyplot', 'scipy.signal', 'scipy.interpolate',
+'scipy.optimize', 'scipy.stats', 'scipy.cluster', 'scipy.cluster.hierarchy', 'scipy.cluster.vq', 'scipy.sparse',
+'scipy.spatial', 'scipy.spatial.distance', 'sklearn', 'sklearn.cluster', 'sklearn.grid_search', 'sklearn.external',
+'matplotlib.gridspec', 'h5py']
+for mod_name in MOCK_MODULES:
+    sys.modules[mod_name] = mock.Mock()
+
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
diff --git a/requirements.txt b/requirements.txt
index b7289b15..01801dc8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-numpy
+numpy==1.9.2
 matplotlib==1.4.3
 scipy==0.15.1
 scikit-learn==0.16.1