diff --git a/src/external/LF_GL/PLGKT_LF.cpp b/src/external/LF_GL/PLGKT_LF.cpp
index 63bb458f..bcf58455 100644
--- a/src/external/LF_GL/PLGKT_LF.cpp
+++ b/src/external/LF_GL/PLGKT_LF.cpp
@@ -37,6 +37,12 @@
 #include "PGKT_LF.h"
 
 //-----------------------------------------------------------------------------
+/**
+ * <p>CTOR
+ *
+ * @param param [0] field (G), [1] width (1/us), [2] hopp (1/us)
+ * @param tmax maximal time to be used, default = 10 us
+ */
 PLGKT_LF::PLGKT_LF(std::vector<double> &param, const double tmax) : fParam(param), fTmax(tmax)
 {
   if (DynamicLGKTLF() == 0)
diff --git a/src/external/LF_GL/main.cpp b/src/external/LF_GL/main.cpp
index 52fe7c62..b0ae2898 100644
--- a/src/external/LF_GL/main.cpp
+++ b/src/external/LF_GL/main.cpp
@@ -57,6 +57,18 @@ void lf_zf_approx(const bool gaussian, const std::vector<double> &param,
 }
 
 // ----------------------------------------------------------------------------
+/**
+ * <p>write the polarization data to an ascii output file.
+ *
+ * @param fln filename
+ * @param zf_approx true for ZF approximation functions, otherwise full integration
+ * @param gaussian_only true for Gaussian, otherwise Gaussian/Lorentzian
+ * @param param [0] field (G), [1] width (1/us), [2] hopp (1/us)
+ * @param tt time vector
+ * @param pol polarization vector
+ *
+ * @return 0 on success, > 0 otherwise
+ */
 int lf_gl_write(const std::string fln, const bool zf_approx,
                 const bool gaussian_only,
                 const std::vector<double> &param,