diff --git a/src/ao_two_e_erf_integrals/README.rst b/src/ao_two_e_erf_integrals/README.rst
new file mode 100644
index 00000000..df48c560
--- /dev/null
+++ b/src/ao_two_e_erf_integrals/README.rst
@@ -0,0 +1,17 @@
+======================
+ao_two_e_erf_integrals
+======================
+
+Here, all two-electron integrals (:math:`erf(\mu r_{12})/r_{12}`) are computed.
+As they have 4 indices and many are zero, they are stored in a map, as defined
+in :file:`utils/map_module.f90`.
+
+The main parameter of this module is :option:`ao_two_e_erf_integrals mu_erf` which is the range-separation parameter. 
+
+To fetch an |AO| integral, use the
+`get_ao_bielec_integral_erf(i,j,k,l,ao_integrals_erf_map)` function, and
+The conventions are:
+* For |AO| integrals : (ij|kl) = (11|22) = <ik|jl> = <12|12>
+
+
+
diff --git a/src/ao_two_e_integrals/README.rst b/src/ao_two_e_integrals/README.rst
new file mode 100644
index 00000000..bb57c4a2
--- /dev/null
+++ b/src/ao_two_e_integrals/README.rst
@@ -0,0 +1,15 @@
+==================
+ao_two_e_integrals
+==================
+
+Here, all two-electron integrals (:math:`1/r_{12}`) are computed.
+As they have 4 indices and many are zero, they are stored in a map, as defined
+in :file:`utils/map_module.f90`.
+
+To fetch an |AO| integral, use the
+`get_ao_bielec_integral(i,j,k,l,ao_integrals_map)` function, and
+The conventions are:
+* For |AO| integrals : (ij|kl) = (11|22) = <ik|jl> = <12|12>
+
+
+
diff --git a/src/dft_utils_in_r/README.rst b/src/dft_utils_in_r/README.rst
new file mode 100644
index 00000000..0b082339
--- /dev/null
+++ b/src/dft_utils_in_r/README.rst
@@ -0,0 +1,14 @@
+==============
+dft_utils_in_r
+==============
+
+This module contains most of the fundamental quantities (AOs, MOs or density derivatives) evaluated in real-space representation that are needed for the various DFT modules. 
+
+As these quantities might be used and re-used, the values at each point of the grid are stored (see ``becke_numerical_grid`` for more information on the grid).  
+
+The main providers for this module are:
+
+# `aos_in_r_array`: values of the |AO| basis on the grid point.
+# `mos_in_r_array`: values of the |MO| basis on the grid point.
+# `one_dm_and_grad_alpha_in_r`: values of the density and its gradienst on the grid points.
+