diff --git a/apps/probability/law/exponential_law.cpp b/apps/probability/law/exponential_law.cpp
index 75d278bbd..97645a626 100644
--- a/apps/probability/law/exponential_law.cpp
+++ b/apps/probability/law/exponential_law.cpp
@@ -25,7 +25,8 @@ bool ExponentialLaw::isContinuous() const {
 
 const char * ExponentialLaw::parameterNameAtIndex(int index) {
   assert(index == 0);
-  return "l";
+  constexpr static char name[] = {Ion::Charset::SmallLambda, 0};
+  return name;
 }
 
 const char * ExponentialLaw::parameterDefinitionAtIndex(int index) {
diff --git a/apps/probability/law/normal_law.cpp b/apps/probability/law/normal_law.cpp
index 3f8b4af3d..0e6400751 100644
--- a/apps/probability/law/normal_law.cpp
+++ b/apps/probability/law/normal_law.cpp
@@ -26,9 +26,11 @@ bool NormalLaw::isContinuous() const {
 const char * NormalLaw::parameterNameAtIndex(int index) {
   assert(index >= 0 && index < 2);
   if (index == 0) {
-    return "u";
+    constexpr static char meanName[] = {Ion::Charset::SmallMu, 0};
+    return meanName;
   } else {
-    return "o";
+    constexpr static char devName[] = {Ion::Charset::SmallSigma, 0};
+    return devName;
   }
 }
 
diff --git a/apps/probability/law/poisson_law.cpp b/apps/probability/law/poisson_law.cpp
index 6bd772702..2da5e5073 100644
--- a/apps/probability/law/poisson_law.cpp
+++ b/apps/probability/law/poisson_law.cpp
@@ -1,6 +1,7 @@
 #include "poisson_law.h"
 #include <assert.h>
 #include <math.h>
+#include <ion.h>
 
 namespace Probability {
 
@@ -23,12 +24,14 @@ bool PoissonLaw::isContinuous() const {
 
 const char * PoissonLaw::parameterNameAtIndex(int index) {
   assert(index == 0);
-  return "l";
+  constexpr static char name[] = {Ion::Charset::SmallLambda, 0};
+  return name;
 }
 
 const char * PoissonLaw::parameterDefinitionAtIndex(int index) {
   assert(index == 0);
-  return "l : parametre";
+  constexpr static char meanDef[] = {Ion::Charset::SmallLambda, ' ', ':', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'r', 'e', 0};
+  return meanDef;
 }
 
 float PoissonLaw::xMin() {