diff --git a/test/ci/debian:testing/Dockerfile b/test/ci/debian:testing/Dockerfile
index 071dba65b..c0b2da0b0 100644
--- a/test/ci/debian:testing/Dockerfile
+++ b/test/ci/debian:testing/Dockerfile
@@ -1,30 +1,34 @@
 FROM debian:testing
 MAINTAINER Nicolas Richart <nicolas.richart@epfl.ch>
 
 # library dependencies
 RUN apt-get -qq update && apt-get -qq -y install \
     g++ gfortran clang cmake \
     openmpi-bin libmumps-dev libscotch-dev \
     libboost-dev libopenblas-dev \
     python3 python3-dev python3-numpy python3-scipy python3-mpi4py \
     && rm -rf /var/lib/apt/lists/*
 
 # for documentation
 RUN apt-get -qq update && apt-get -qq -y install \
-    python3-sphinx python3-sphinx-rtd-theme python3-breathe doxygen graphviz \
+    python3-sphinx \
+    python3-sphinxcontrib.bibtex \
+    python3-sphinx-rtd-theme \
+    python3-breathe \
+    doxygen graphviz \
     && rm -rf /var/lib/apt/lists/*
 
 # for ci
 RUN apt-get -qq update && apt-get -qq -y install \
     gmsh python3-pytest \
     ccache clang-format python3-flake8 clang-tidy \
     curl git xsltproc jq \
     gcovr llvm binutils \
     && rm -rf /var/lib/apt/lists/*
 
 COPY .openmpi /root/.openmpi
 
 # for debug
 RUN apt-get -qq update && apt-get -qq -y install \
     gdb valgrind \
     && rm -rf /var/lib/apt/lists/*