diff --git a/common/constants.org b/common/constants.org
new file mode 100644
index 0000000..626e916
--- /dev/null
+++ b/common/constants.org
@@ -0,0 +1,102 @@
+#+begin_src elisp tangle: no :results none
+(setq pwd (file-name-directory buffer-file-name))
+(setq name (file-name-nondirectory (substring buffer-file-name 0 -4)))
+(setq lib (concat pwd "lib/"))
+(setq testdir (concat pwd "test/"))
+(setq mli (concat lib name ".mli"))
+(setq ml  (concat lib name ".ml"))
+(setq test-ml  (concat testdir name ".ml"))
+(org-babel-tangle)
+#+end_src 
+
+* Constants
+  :PROPERTIES:
+  :header-args: :noweb yes :comments both
+  :END:
+
+  All constants used in the program.
+  
+
+   #+begin_src ocaml :tangle (eval mli)
+   #+end_src
+
+   #+begin_src ocaml :tangle (eval ml) :exports none
+   #+end_src
+
+** Thresholds
+
+   
+*** ~epsilon~
+
+    Value below which a float is considered null. Default is
+    \epsilon = 2.10^{-15}.
+
+    #+begin_src ocaml :tangle (eval mli)
+val epsilon : float
+    #+end_src
+
+    #+begin_src ocaml :tangle (eval ml) :exports none
+let epsilon = 2.e-15
+    #+end_src
+
+
+*** ~integrals_cutoff~
+
+    Cutoff value for integrals. Default is \epsilon .
+    #+begin_src ocaml :tangle (eval mli)
+val integrals_cutoff : float
+    #+end_src
+
+    #+begin_src ocaml :tangle (eval ml) :exports none
+let integrals_cutoff = epsilon
+    #+end_src
+
+
+** Mathematical constants 
+
+   | ~pi~             | $\pi = 3.141~592~653~589~793~12$ |
+   | ~two_pi~         | $2 \pi$                          |
+   | ~sq_pi~          | $\sqrt{\pi}$                     |
+   | ~sq_pi_over_two~ | $\sqrt{\pi} / 2$                 |
+   | ~pi_inv~         | $1 / \pi$                        |
+   | ~two_over_sq_pi~ | $2 / \sqrt{\pi}$                 |
+    
+   #+begin_src ocaml :tangle (eval mli)
+val pi             : float
+val two_pi         : float
+val sq_pi          : float
+val sq_pi_over_two : float
+val pi_inv         : float
+val two_over_sq_pi : float
+   #+end_src
+
+   #+begin_src ocaml :tangle (eval ml) :exports none
+let pi             = acos (-1.)
+let two_pi         = 2. *. pi
+let sq_pi          = sqrt pi
+let sq_pi_over_two = sq_pi *. 0.5
+let pi_inv         = 1. /. pi
+let two_over_sq_pi = 2. /. sq_pi
+   #+end_src
+
+    
+** Physical constants
+   
+   | ~a0~       | Bohr's radius : $a_0 = 0.529~177~210~67(23)$ angstrom |
+   | ~a0_inv~   | $1 / a_0$                                             |
+   | ~ha_to_ev~ | Hartree to eV conversion factor : $27.211~386~02(17)$ |
+   | ~ev_to_ha~ | eV to Hartree conversion factor : 1 / ~ha_to_ev~      |
+    
+   #+begin_src ocaml :tangle (eval mli)
+val a0       : float
+val a0_inv   : float
+val ha_to_ev : float
+val ev_to_ha : float
+   #+end_src
+
+   #+begin_src ocaml :tangle (eval ml) :exports none
+let a0 = 0.529_177_210_67
+let a0_inv = 1. /. a0
+let ha_to_ev = 27.211_386_02
+let ev_to_ha = 1. /. ha_to_ev
+   #+end_src
diff --git a/common/lib/constants.ml b/common/lib/constants.ml
index f96a4c9..e5fb497 100644
--- a/common/lib/constants.ml
+++ b/common/lib/constants.ml
@@ -1,15 +1,27 @@
+(* [[file:../constants.org::*Constants][Constants:2]] *)
+
+(* Constants:2 ends here *)
+
+(* [[file:../constants.org::*~epsilon~][~epsilon~:2]] *)
 let epsilon = 2.e-15
+(* ~epsilon~:2 ends here *)
+
+(* [[file:../constants.org::*~integrals_cutoff~][~integrals_cutoff~:2]] *)
 let integrals_cutoff = epsilon
+(* ~integrals_cutoff~:2 ends here *)
 
-(** Constants *)
-let pi = acos (-1.)
-let two_pi = 2. *. pi
-let sq_pi = sqrt pi
+(* [[file:../constants.org::*Mathematical constants][Mathematical constants:2]] *)
+let pi             = acos (-1.)
+let two_pi         = 2. *. pi
+let sq_pi          = sqrt pi
 let sq_pi_over_two = sq_pi *. 0.5
-let pi_inv = 1. /. pi
-let two_over_sq_pi = 2. /. (sqrt pi)
+let pi_inv         = 1. /. pi
+let two_over_sq_pi = 2. /. sq_pi
+(* Mathematical constants:2 ends here *)
 
+(* [[file:../constants.org::*Physical constants][Physical constants:2]] *)
 let a0 = 0.529_177_210_67
 let a0_inv = 1. /. a0
 let ha_to_ev = 27.211_386_02
 let ev_to_ha = 1. /. ha_to_ev
+(* Physical constants:2 ends here *)
diff --git a/common/lib/constants.mli b/common/lib/constants.mli
index 5997ef3..9326ba6 100644
--- a/common/lib/constants.mli
+++ b/common/lib/constants.mli
@@ -1,45 +1,64 @@
-(** All constants used in the program.
- *)
+(* Constants
+ *   :PROPERTIES:
+ *   :header-args: :noweb yes :comments both
+ *   :END:
+ * 
+ *   All constants used in the program. *)
+  
 
-(** {2 Thresholds } *)
 
+(* [[file:../constants.org::*Constants][Constants:1]] *)
+
+(* Constants:1 ends here *)
+
+(* ~epsilon~
+ * 
+ *     Value below which a float is considered null. Default is
+ *     \epsilon = 2.10^{-15}. *)
+
+
+(* [[file:../constants.org::*~epsilon~][~epsilon~:1]] *)
 val epsilon : float
-(** Value below which a float is considered null. Default is {% $\epsilon$ %} = 10{^-20}. *)
+(* ~epsilon~:1 ends here *)
 
+(* ~integrals_cutoff~
+ * 
+ *     Cutoff value for integrals. Default is \epsilon . *)
+
+(* [[file:../constants.org::*~integrals_cutoff~][~integrals_cutoff~:1]] *)
 val integrals_cutoff : float
-(** Cutoff value for integrals. Default is 10{^-15}. *)
+(* ~integrals_cutoff~:1 ends here *)
 
-(** {2 Mathematical constants } *)
-
-val pi : float
-(** {% $\pi$ %} = 3.141_592_653_589_793_12 *)
-
-val two_pi : float
-(** {% $2\pi$ %} *)
-
-val sq_pi : float
-(** {% $\sqrt{\pi}$ %} *)
+(* Mathematical constants 
+ * 
+ *    | ~pi~             | $\pi = 3.141~592~653~589~793~12$ |
+ *    | ~two_pi~         | $2 \pi$                          |
+ *    | ~sq_pi~          | $\sqrt{\pi}$                     |
+ *    | ~sq_pi_over_two~ | $\sqrt{\pi} / 2$                 |
+ *    | ~pi_inv~         | $1 / \pi$                        |
+ *    | ~two_over_sq_pi~ | $2 / \sqrt{\pi}$                 | *)
+    
 
+(* [[file:../constants.org::*Mathematical constants][Mathematical constants:1]] *)
+val pi             : float
+val two_pi         : float
+val sq_pi          : float
 val sq_pi_over_two : float
-(** {% $\frac{\sqrt{\pi}}{2}$ %} *)
-
-val pi_inv : float
-(** {% $\frac{1}{\pi}$ %} *)
-
+val pi_inv         : float
 val two_over_sq_pi : float
-(** {% $\frac{2}{\sqrt{\pi}}$ %} *)
+(* Mathematical constants:1 ends here *)
 
-(** {2 Physical constants} *)
-
-val a0 : float
-(** Bohr radius : {% $a_0$ %} = 0.529 177 210 67(23) Angstrom *)
-
-val a0_inv : float
-(** {% $\frac{1}{a_0}$ %} *)
+(* Physical constants
+ *    
+ *    | ~a0~       | Bohr's radius : $a_0 = 0.529~177~210~67(23)$ angstrom |
+ *    | ~a0_inv~   | $1 / a_0$                                             |
+ *    | ~ha_to_ev~ | Hartree to eV conversion factor : $27.211~386~02(17)$ |
+ *    | ~ev_to_ha~ | eV to Hartree conversion factor : 1 / ~ha_to_ev~      | *)
+    
 
+(* [[file:../constants.org::*Physical constants][Physical constants:1]] *)
+val a0       : float
+val a0_inv   : float
 val ha_to_ev : float
-(** Hartree to eV conversion factor :: 27.211 386 02(17) *)
-
 val ev_to_ha : float
-(** eV to Hartree conversion factor : 1/{ha_to_ev} *)
-
+(* Physical constants:1 ends here *)