diff --git a/src/include/Commons.h b/src/include/Commons.h
index ebddabf6532ad581745d8601a75e4d0cffadda85..d89a023c74139fc9ff0876746487de1ab2294b41 100644
--- a/src/include/Commons.h
+++ b/src/include/Commons.h
@@ -88,21 +88,21 @@ public:
   dcomplex *fsas;
   //! \brief QUESTION: definition?
   dcomplex *vint;
-  //! \brief QUESTION: definition?
+  //! \brief Components of the scattered field intensities.
   dcomplex **vints;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere scattering cross-sections.
   double *sscs;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere extinction cross-sections.
   double *sexs;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere absorption cross-sections.
   double *sabs;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere scattering efficiencies.
   double *sqscs;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere extinction efficiencies.
   double *sqexs;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere absorption efficiencies.
   double *sqabs;
-  //! \brief QUESTION: definition?
+  //! \brief Single sphere geometric cross-section vector.
   double *gcsv;
   //! \brief Vector of sphere X coordinates.
   double *rxx;
@@ -169,7 +169,7 @@ public:
   dcomplex *ris;
   //! \brief QUESTION: definition?
   dcomplex *dlri;
-  //! \brief QUESTION: definition?
+  //! \brief Vector of dielectric constants.
   dcomplex *dc0;
   //! \brief QUESTION: definition?
   dcomplex *vkt;
@@ -216,13 +216,13 @@ public:
   dcomplex tfsas;
   //! \brief QUESTION: definition?
   dcomplex **tsas;
-  //! \brief QUESTION: definition?
+  //! \brief Total geometric cross-section.
   double gcs;
-  //! \brief QUESTION: definition?
+  //! \brief Total scattering cross-section.
   double scs;
-  //! \brief QUESTION: definition?
+  //! \brief Total extinction cross-section.
   double ecs;
-  //! \brief QUESTION: definition?
+  //! \brief Total absorption cross-section.
   double acs;
 
   /*! \brief C3 instance constructor.
@@ -269,17 +269,17 @@ public:
   int lmtpos;
   //! \brief Internal field expansion order.
   int li;
-  //! \brief QUESTION: definition?
+  //! \brief NLIM = LI * (LI + 2)
   int nlim;
   //! \brief External field expansion order.
   int le;
-  //! \brief QUESTION: definition?
+  //! \brief NLEM = LE * (LE + 2)
   int nlem;
   //! \brief Maximum field expansion order.
   int lm;
   //! \brief Number of spheres.
   int nsph;
-  //! \brief QUESTION: definition?
+  //! \brief NV3J = (LM * (LM + 1) * (2 * LM + 7)) / 6
   int nv3j;
 
   /*! \brief C4 instance constructor.
@@ -321,21 +321,21 @@ class C1_AddOns {
 protected:
   //! \brief Number of spheres.
   int nsph;
-  //! \brief QUESTION: definition?
+  //! \brief NLEMT = 2 * (LE * (LE + 2))
   int nlemt;
-  //! \brief Maximum expansion order plus one. QUESTION: correct?
+  //! \brief LMPO = LM + 1
   int lmpo;
-  //! \brief QUESTION: definition?
+  //! \brief LITPO = 2 * LI + 1
   int litpo;
-  //! \brief QUESTION: definition?
+  //! \brief LMTPO = 2 * LM + 1
   int lmtpo;
-  //! \brief QUESTION: definition?
+  //! \brief LITPOS = LITPO * LITPO
   int litpos;
-  //! \brief QUESTION: definition?
+  //! \brief LMTPOS = LMTPO * LMTPO
   int lmtpos;
-  //! \brief QUESTION: definition?
+  //! \brief NV3J = (LM * (LM + 1) * (2 * LM + 7)) / 6
   int nv3j;
-  //! \brief QUESTION: definition?
+  //! \brief Maximum field expansion order.
   int lm;
 
 public:
@@ -351,7 +351,7 @@ public:
   dcomplex *vyj0;
   //! \brief QUESTION: definition?
   dcomplex **am0m;
-  //! \brief QUESTION: definition?
+  //! \brief Vectorized AM0M matrix.
   dcomplex *am0v;
   //! \brief QUESTION: definition?
   dcomplex *vintm;
@@ -469,9 +469,9 @@ protected:
   int sam_size_0;
 
 public:
-  //! \brief QUESTION: definition?
+  //! \brief NLEM = LE * (LE + 2)
   int nlem;
-  //! \brief QUESTION: definition?
+  //! \brief NLEMT = 2 * LE * (LE + 2)
   int nlemt;
   //! \brief QUESTION: definition?
   dcomplex **gis;
@@ -482,10 +482,10 @@ public:
 
   /*! \brief C9 instance constructor.
    *
-   * \param ndi: `int` QUESTION: definition?
-   * \param nlem: `int` QUESTION: definition?
-   * \param ndit: `int` QUESTION: definition?
-   * \param nlemt: `int` QUESTION: definition?
+   * \param ndi: `int` NDI = NSPH * LI * (LI + 2)
+   * \param nlem: `int` NLEM = LE * (LE + 2)
+   * \param ndit: `int` NDIT = 2 * NSPH * LI * (LI + 2)
+   * \param nlemt: `int` NLEMT = 2 * LE * (LE + 2)
    */
   C9(int ndi, int nlem, int ndit, int nlemt);
 
@@ -564,7 +564,7 @@ public:
   C6 *c6;
   //! \brief Pointer to a C9 structure.
   C9 *c9;
-  //! \brief Pointer to a formatted output file.
+  //! \brief Vector of geometric asymmetry factors.
   double *gaps;
   double **tqse;
   dcomplex **tqspe;
@@ -599,6 +599,7 @@ public:
   double *unsmp;
   double *upmp;
   double *upsmp;
+  //! \brief Scattering angle.
   double scan;
   double cfmp;
   double sfmp;
@@ -609,7 +610,7 @@ public:
   dcomplex *am_vector;
   dcomplex **am;
   dcomplex arg;
-  //! \brief Wave vector.
+  //! \brief Vacuum magnitude of wave vector.
   double vk;
   //! \brief Wave number.
   double wn;