diff --git a/qpms/vswf.c b/qpms/vswf.c
index 06bb210..5195dee 100644
--- a/qpms/vswf.c
+++ b/qpms/vswf.c
@@ -1,4 +1,5 @@
 #include "vswf.h"
+#include <math.h>
 
 // Legendre functions also for negative m, see DLMF 14.9.3
 qpms_errno_t qpms_legendre_deriv_y_fill(double *target, double *target_deriv, double x, qpms_l_t lMax,
@@ -25,12 +26,22 @@ qpms_errno_t qpms_legendre_deriv_y_fill(double *target, double *target_deriv, do
 				// viz DLMF 14.9.3, čert ví, jak je to s cs fasí.
 				double factor = exp(lgamma(l-m+1)-lgamma(n+m+1))*((m%2)?-1:1);
 				target[y] = factor * legendre_tmp[i];
-				target_deriv[y] = factor * legendre_deriv_tmp;
+				target_deriv[y] = factor * legendre_deriv_tmp[i];
 				}
 			break;
 		case GSL_SF_LEGENDRE_SCHMIDT:
 		case GSL_SF_LEGENDRE_SPHARM:
 		case GSL_SF_LEGENDRE_FULL:
+			for (qpms_l_t l = 0; l <= lMax; ++l)
+				for (qpms_m_t m = 1; m <= l; ++m) {
+				qpms_y_t y = gpms_mn2y(-m,l);
+				size_t i = gsl_sf_legenre_array_index(l,m);
+				// viz DLMF 14.9.3, čert ví, jak je to s cs fasí.
+				double factor = ((m%2)?-1:1); // this is the difference from the unnormalised case
+				target[y] = factor * legendre_tmp[i];
+				target_deriv[y] = factor * legendre_deriv_tmp[i];
+				}
+			break;
 		default:
 			abort(); //NI
 			break;
diff --git a/qpms/vswf.h b/qpms/vswf.h
index 3615669..8f989bc 100644
--- a/qpms/vswf.h
+++ b/qpms/vswf.h
@@ -20,9 +20,15 @@ typedef struct {
 } qpms_vswfset_sph_t;
 
 
-double *qpms_legenre_deriv_y_get(double x, qpms_l_t lMax, 
-		gsle_sf_legendre_t lnorm, double csphase);
-qpms_errno_t qpms_legenre_deriv_y_fill(double *where, double x, 
+/*
+ * N.B. for the norm definitions, see
+ * https://www.gnu.org/software/gsl/manual/html_node/Associated-Legendre-Polynomials-and-Spherical-Harmonics.html
+ * ( gsl/specfunc/legendre_source.c and 7.24.2 of gsl docs
+ * 
+
+double *qpms_legendre_deriv_y_get(double x, qpms_l_t lMax, 
+		gsle_sf_legendre_t lnorm, double csphase); //FIXME what about derivative?
+qpms_errno_t qpms_legendre_deriv_y_fill(double *where, double *where_deriv, double x, 
 		qpms_l_t lMax, gsl_sf_legendre_t lnorm, double csphase); //NI
 
 qpms_vswfset_sph_t *qpms_vswfset_make(qpms_l_t lMax, sph_t kdlj,