diff --git a/libsharp/sharp.h b/libsharp/sharp.h
index fed7361..88c247f 100644
--- a/libsharp/sharp.h
+++ b/libsharp/sharp.h
@@ -64,6 +64,9 @@ typedef struct
   unsigned long long opcnt;
   } sharp_job;
 
+/*! \defgroup jobgroup Functionality for defining and executing SHTs */
+/*! \{ */
+
 /*! Initializes \a job with the appropriate parameters to perform the required
   SHT.
   \param type the type of SHT
diff --git a/libsharp/sharp_lowlevel.h b/libsharp/sharp_lowlevel.h
index 3899abb..6faf5df 100644
--- a/libsharp/sharp_lowlevel.h
+++ b/libsharp/sharp_lowlevel.h
@@ -135,7 +135,7 @@ void sharp_destroy_geom_info (sharp_geom_info *info);
 
 /*! \} */
 
-/*! \defgroup jobgroup Functionality for defining and executing SHTs */
+/*! \defgroup lowlevelgroup Low-level libsharp SHT interface */
 /*! \{ */
 
 /*! Enumeration of SHARP job types. */
@@ -144,10 +144,32 @@ typedef enum { SHARP_MAP2ALM,       /*!< analysis */
                SHARP_ALM2MAP_DERIV1 /*!< synthesis of first derivatives */
              } sharp_jobtype;
 
+/*! Performs a libsharp SHT job. The interface deliberately does not use
+  the C99 "complex" data type, in order to be callable from C. 
+  \param type the type of SHT
+  \param spin the spin of the quantities to be transformed
+  \param add_output if 0, the output arrays will be overwritten,
+    else the result will be added to the output arrays.
+  \param alm contains pointers to the a_lm coefficients. If \a spin==0,
+    alm[0] points to the a_lm of the first SHT, alm[1] to those of the second
+    etc. If \a spin>0, alm[0] and alm[1] point to the a_lm of the first SHT,
+    alm[2] and alm[3] to those of the second, etc. The exact data type of \a alm
+    depends on the \a dp parameter.
+  \param map contains pointers to the maps. If \a spin==0,
+    map[0] points to the map of the first SHT, map[1] to that of the second
+    etc. If \a spin>0, map[0] and map[1] point to the maps of the first SHT,
+    map[2] and map[3] to those of the second, etc. The exact data type of \a map
+    depends on the \a dp parameter.
+  \param ntrans the number of simultaneous SHTs
+  \param dp if 0, the \a alm is expected to have the type "complex float **"
+    and \a map is expected to have the type "float **"; otherwise the expected
+    types are "complex double **" and "double **", respectively. */
 void sharp_execute_ll (sharp_jobtype type, int spin, int add_output, void **alm,
   void **map, const sharp_geom_info *geom_info, const sharp_alm_info *alm_info,
   int ntrans, int dp);
 
+/*! \} */
+
 #ifdef __cplusplus
 }
 #endif