diff --git a/configure b/configure
index 2599fbbc..6440710f 100755
--- a/configure
+++ b/configure
@@ -292,6 +292,9 @@ EOF
                 # Special commands for Travis CI
                 chmod +x "${QP_ROOT}"/external/opam_installer.sh
                 rm --force ${QP_ROOT}/bin/opam
+                if [[ -n ${NO_CACHE} ]] ; then
+                        rm -rf ${HOME}/.opam
+                fi
                 export OPAMROOT=${HOME}/.opam
                 cat << EOF | bash ${QP_ROOT}/external/opam_installer.sh --no-backup 
 ${QP_ROOT}/bin
@@ -301,9 +304,9 @@ ${QP_ROOT}/bin
 EOF
 
                 rm ${QP_ROOT}/external/opam_installer.sh
-                source ${OPAMROOT}/opam-init/init.sh > /dev/null 2> /dev/null || true
-
-                opam switch create ocaml-base-compiler.4.07.1
+#                source ${OPAMROOT}/opam-init/init.sh > /dev/null 2> /dev/null || true
+#
+#                opam switch create ocaml-base-compiler.4.07.1
                 opam init --verbose --yes --compiler=4.07.1 --disable-sandboxing
 
                 eval $(opam env)
@@ -322,8 +325,8 @@ EOF
                   | sh \${QP_ROOT}/external/opam_installer.sh 
 EOF
                 rm ${QP_ROOT}/external/opam_installer.sh
-                source ${OPAMROOT}/opam-init/init.sh > /dev/null 2> /dev/null || true
-                opam switch create ocaml-base-compiler.4.07.1     || exit 1
+#                source ${OPAMROOT}/opam-init/init.sh > /dev/null 2> /dev/null || true
+#                opam switch create ocaml-base-compiler.4.07.1     || exit 1
                 opam init --verbose --yes --compiler=4.07.1 --disable-sandboxing
                 eval $(opam env)
 EOF
diff --git a/docs/source/research.bib b/docs/source/research.bib
index 479b920a..e6c75b9e 100644
--- a/docs/source/research.bib
+++ b/docs/source/research.bib
@@ -9,24 +9,28 @@
         url = {https://arxiv.org/abs/1907.01245}
 }
 
-@article{Dash2019May,
-        author = {Dash, Monika and Feldt, Jonas and Moroni, Saverio and Scemama, Anthony and Filippi, Claudia},
-        title = {{Excited states with selected CI-QMC: chemically accurate excitation energies and geometries}},
-        journal = {arXiv},
-        year = {2019},
-        month = {May},
-        eprint = {1905.06737},
-        url = {https://arxiv.org/abs/1905.06737}
+
+@article{Burton_2019,
+        doi = {10.1021/acs.jctc.9b00441},
+        url = {https://doi.org/10.1021%2Facs.jctc.9b00441},
+        year = 2019,
+        month = {aug},
+        publisher = {American Chemical Society ({ACS})},
+        author = {Hugh G. A. Burton and Alex J.W. Thom},
+        title = {A General Approach for Multireference Ground and Excited States using Non-Orthogonal Configuration Interaction},
+        journal = {Journal of Chemical Theory and Computation}
 }
 
-@article{Burton2019May,
-        author = {Burton, Hugh G. A. and Thom, Alex J. W.},
-        title = {{A General Approach for Multireference Ground and Excited States using Non-Orthogonal Configuration Interaction}},
-        journal = {arXiv},
-        year = {2019},
-        month = {May},
-        eprint = {1905.02626},
-        url = {https://arxiv.org/abs/1905.02626}
+
+@article{Dash_2019,
+        doi = {10.1021/acs.jctc.9b00476},
+        url = {https://doi.org/10.1021%2Facs.jctc.9b00476},
+        year = 2019,
+        month = {aug},
+        publisher = {American Chemical Society ({ACS})},
+        author = {Monika Dash and Jonas Feldt and Saverio Moroni and Anthony Scemama and Claudia Filippi},
+        title = {Excited States with Selected Configuration Interaction-Quantum Monte Carlo: Chemically Accurate Excitation Energies and Geometries},
+        journal = {Journal of Chemical Theory and Computation}
 }
 
 
@@ -43,6 +47,19 @@
         pages = {084103},
         author = {Anthony Fert{\'{e}} and Emmanuel Giner and Julien Toulouse},
         title = {Range-separated multideterminant density-functional theory with a short-range correlation functional of the on-top pair density},
+}
+
+@article{Caffarel_2019,
+        doi = {10.1063/1.5114703},
+        url = {https://doi.org/10.1063%2F1.5114703},
+        year = 2019,
+        month = {aug},
+        publisher = {{AIP} Publishing},
+        volume = {151},
+        number = {6},
+        pages = {064101},
+        author = {Michel Caffarel},
+        title = {Evaluating two-electron-repulsion integrals over arbitrary orbitals using zero variance Monte Carlo: Application to full configuration interaction calculations with Slater-type orbitals},
         journal = {The Journal of Chemical Physics}
 }