diff --git a/examples/pdegen/mld_dexample_1lev.f90 b/examples/pdegen/mld_dexample_1lev.f90
index 35adba4d..acd9210d 100644
--- a/examples/pdegen/mld_dexample_1lev.f90
+++ b/examples/pdegen/mld_dexample_1lev.f90
@@ -109,7 +109,7 @@ contains
     a3=1.d0/80
   end function a3
   function g(x,y,z)
-    use psb_base_mod, only : psb_dpk_, done
+    use psb_base_mod, only : psb_dpk_, done, dzero
     real(psb_dpk_) ::  g
     real(psb_dpk_), intent(in) :: x,y,z
     g = dzero
diff --git a/examples/pdegen/mld_dexample_ml.f90 b/examples/pdegen/mld_dexample_ml.f90
index bfb7f8f8..d6c86bfd 100644
--- a/examples/pdegen/mld_dexample_ml.f90
+++ b/examples/pdegen/mld_dexample_ml.f90
@@ -114,7 +114,7 @@ contains
     a3=1.d0/80
   end function a3
   function g(x,y,z)
-    use psb_base_mod, only : psb_dpk_, done
+    use psb_base_mod, only : psb_dpk_, done, dzero
     real(psb_dpk_) ::  g
     real(psb_dpk_), intent(in) :: x,y,z
     g = dzero
diff --git a/examples/pdegen/mld_sexample_1lev.f90 b/examples/pdegen/mld_sexample_1lev.f90
index 8863e29a..597dce7d 100644
--- a/examples/pdegen/mld_sexample_1lev.f90
+++ b/examples/pdegen/mld_sexample_1lev.f90
@@ -113,7 +113,7 @@ contains
     a3=1.e0/80
   end function a3
   function g(x,y,z)
-    use psb_base_mod, only : psb_spk_, sone
+    use psb_base_mod, only : psb_spk_, sone, szero
     real(psb_spk_) ::  g
     real(psb_spk_), intent(in) :: x,y,z
     g = szero
diff --git a/examples/pdegen/mld_sexample_ml.f90 b/examples/pdegen/mld_sexample_ml.f90
index 23b1db30..4f6cd59c 100644
--- a/examples/pdegen/mld_sexample_ml.f90
+++ b/examples/pdegen/mld_sexample_ml.f90
@@ -113,7 +113,7 @@ contains
     a3=1.e0/80
   end function a3
   function g(x,y,z)
-    use psb_base_mod, only : psb_spk_, sone
+    use psb_base_mod, only : psb_spk_, sone, szero
     real(psb_spk_) ::  g
     real(psb_spk_), intent(in) :: x,y,z
     g = szero