diff --git a/doc/user-manual/bibliography.bib.sav b/doc/user-manual/bibliography.bib.sav
new file mode 100644
index 0000000..b8b6483
--- /dev/null
+++ b/doc/user-manual/bibliography.bib.sav
@@ -0,0 +1,77 @@
+% Encoding: UTF-8
+
+@InProceedings{boris1970relativistic,
+  author    = {Boris, Jay P},
+  booktitle = {Proc. Fourth Conf. Num. Sim. Plasmas},
+  title     = {Relativistic plasma simulation-optimization of a hybrid code},
+  year      = {1970},
+  pages     = {3--67},
+}
+
+@article{higginson2020corrected,
+  title={A corrected method for Coulomb scattering in arbitrarily weighted particle-in-cell plasma simulations},
+  author={Higginson, Drew Pitney and Holod, Ihor and Link, Anthony},
+  journal={Journal of Computational Physics},
+  volume={413},
+  pages={109450},
+  year={2020},
+  publisher={Elsevier}
+}
+
+@Misc{gfortranURL,
+  author       = {GNU Project},
+  title        = {gfortran - the GNU Fortran compiler},
+  howpublished = {\url{https://gcc.gnu.org/wiki/GFortran}},
+}
+
+@Misc{ifortURL,
+  author       = {Intel\textsuperscript{\textregistered}},
+  title        = {Intel\textsuperscript{\textregistered} Fortran Compiler},
+  howpublished = {\url{https://software.intel.com/content/www/us/en/develop/tools/oneapi/components/fortran-compiler.html}},
+}
+
+@Misc{openblasURL,
+  title        = {OpenBLAS, an optimized BLAS library},
+  howpublished = {\url{https://www.openblas.net/}},
+}
+
+@Misc{jsonfortranURL,
+  title        = {JSON-Fortran},
+  howpublished = {\url{https://github.com/jacobwilliams/json-fortran}},
+}
+
+@Misc{jsonURL,
+  title        = {JSON, JavaScript Object Notation},
+  howpublished = {\url{https://www.json.org/json-en.html}},
+}
+
+@Misc{gmshURL,
+  author       = {Christophe Geuzaine and Jean-François Remacle},
+  title        = {Gmsh},
+  howpublished = {\url{https://gmsh.info/}},
+}
+
+@Article{welford1962note,
+  author    = {Welford, BP},
+  journal   = {Technometrics},
+  title     = {Note on a method for calculating corrected sums of squares and products},
+  year      = {1962},
+  number    = {3},
+  pages     = {419--420},
+  volume    = {4},
+  publisher = {Taylor \& Francis},
+}
+
+@Article{sherlock2008monte,
+  author    = {Sherlock, Mark},
+  journal   = {Journal of Computational Physics},
+  title     = {A Monte-Carlo method for Coulomb collisions in hybrid plasma models},
+  year      = {2008},
+  number    = {4},
+  pages     = {2286--2292},
+  volume    = {227},
+  groups    = {Particle-in-cell},
+  publisher = {Elsevier},
+}
+
+@Comment{jabref-meta: databaseType:bibtex;}
diff --git a/doc/user-manual/fpakc_UserManual.pdf b/doc/user-manual/fpakc_UserManual.pdf
index 2453bb7..37d8014 100644
Binary files a/doc/user-manual/fpakc_UserManual.pdf and b/doc/user-manual/fpakc_UserManual.pdf differ
diff --git a/doc/user-manual/fpakc_UserManual.tex b/doc/user-manual/fpakc_UserManual.tex
index daf42c3..fd48ed2 100644
--- a/doc/user-manual/fpakc_UserManual.tex
+++ b/doc/user-manual/fpakc_UserManual.tex
@@ -708,11 +708,15 @@ make
                                   \begin{itemize}
                                     \item \textbf{species}: Character.
                                                             Name of species as defined in the object \textbf{species}.
-                                    \item \textbf{file}:    Character.
-                                                            Output file from previous run used as an initial state for the species.
-                                                            The file format must be the same as in \textbf{geometry.meshType}
-                                                            Initial particles are assumed to have a Maxwellian distribution.
-                                                            File must be located at \textbf{output.path}.
+                                    \item \textbf{file}: Character.
+                                                         Output file from previous run used as an initial state for the species.
+                                                         The file format must be the same as in \textbf{geometry.meshType}
+                                                         Initial particles are assumed to have a Maxwellian distribution.
+                                                         File must be located at \textbf{output.path}.
+                                    \item \textbf{particlesPerCell}: Integer.
+                                                                     Optional.
+                                                                     Initial number of particles per cell.
+                                                                     If not, the number of particles per cell will be assigned based on the species weight and the cell volume.
                                   \end{itemize}
         \end{itemize}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/modules/init/moduleInput.f90 b/src/modules/init/moduleInput.f90
index 7a1b206..e30bf97 100644
--- a/src/modules/init/moduleInput.f90
+++ b/src/modules/init/moduleInput.f90
@@ -324,7 +324,8 @@ MODULE moduleInput
       REAL(8):: densityCen
       !Mean velocity and temperature at particle position
       REAL(8):: velocityXi(1:3), temperatureXi
-      INTEGER:: nNewPart = 0.D0
+      INTEGER:: nNewPart = 0
+      REAL(8):: weight = 0.D0
       CLASS(meshCell), POINTER:: cell
       TYPE(particle), POINTER:: partNew
       REAL(8):: vTh
@@ -343,6 +344,9 @@ MODULE moduleInput
           !Reads node values at the nodes
           filename = path // spFile
           CALL mesh%readInitial(filename, density, velocity, temperature)
+          !Check if initial number of particles is given
+          CALL config%get(object // '.particlesPerCell', nNewPart, found)
+
           !For each volume in the node, create corresponding particles
           DO e = 1, mesh%numCells
             !Scale variables
@@ -355,7 +359,11 @@ MODULE moduleInput
             densityCen = mesh%cells(e)%obj%gatherF((/ 0.D0, 0.D0, 0.D0 /), nNodes, sourceScalar)
 
             !Calculate number of particles
-            nNewPart = INT(densityCen * (mesh%cells(e)%obj%volume*Vol_ref) / species(sp)%obj%weight)
+            IF (.NOT. found) THEN
+              nNewPart = FLOOR(densityCen * (mesh%cells(e)%obj%volume*Vol_ref) / species(sp)%obj%weight)
+
+            END IF
+            weight = densityCen * (mesh%cells(e)%obj%volume*Vol_ref) / REAL(nNewPart)
 
             !Allocate new particles
             DO p = 1, nNewPart
@@ -392,7 +400,7 @@ MODULE moduleInput
 
               partNew%n_in   = .TRUE.
 
-              partNew%weight = species(sp)%obj%weight
+              partNew%weight = weight
 
               !Assign particle to temporal list of particles
               CALL partInitial%add(partNew)