diff --git a/src/sigma.f b/src/sigma.f
index c424386..37b5289 100755
--- a/src/sigma.f
+++ b/src/sigma.f
@@ -266,7 +266,7 @@ subroutine dkw(i, j, n, m, rho, rho_a,
          rgamma = real(gamma)
 
          call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
-         if (0) then
+         if (.false.) then
          if(rgamma .ge. 1.0e-08)
      .      call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
 
@@ -866,7 +866,7 @@ subroutine delta_(i, j, n, m, rho, rho_a,
          rgamma = real(gamma)
 
          call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
-         if (0) then
+         if (.false.) then
          if(rgamma .ge. 1.0e-08)
      .      call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
 
@@ -1162,7 +1162,7 @@ subroutine sigmad_cql3d(i, j, n, m, rho, rho_a,
          rgamma = real(gamma)
 
          call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
-         if (0) then
+         if (.false.) then
          if(rgamma .ge. 1.0e-08)
      .      call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
 
@@ -1748,7 +1748,7 @@ subroutine sigmad_cql3d_e(i, j, n, m, rho, rho_a,
          rgamma = real(gamma)
 
          call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
-         if (0) then
+         if (.false.) then
          if(rgamma .ge. 1.0e-08)
      .      call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
 
@@ -2371,7 +2371,7 @@ subroutine sigmad_cql3d_1(i, j, n, m, rho, rho_a,
 
 
          call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
-         if (0) then
+         if (.false.) then
          if(rgamma .ge. 1.0e-08)
      .      call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
 
@@ -2977,7 +2977,7 @@ subroutine sigmad_cql3d_2(i, j, n, m, rho, rho_a,
 
 
          call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)
-         if (0) then
+         if (.false.) then
          if(rgamma .ge. 1.0e-08)
      .      call besiexp(gamma, lmax, exil, exilp, lmaxdim, exilovergam)