diff --git a/Sample/Material/Material.cpp b/Sample/Material/Material.cpp
index 1c1ffc83596cd03a43f607794d2cf5024e18ac77..40e4af05b0fa9cae26c6a391bba049e14eba7115 100644
--- a/Sample/Material/Material.cpp
+++ b/Sample/Material/Material.cpp
@@ -81,10 +81,10 @@ void Material::checkRefractiveIndex(double wavelength) const
 {
     const complex_t n = refractiveIndex(wavelength);
     if (n.real() < 0.9 || n.real() > 1.1) {
-	std::stringstream msg;
-	msg << "Refractive index " << n << " at wavelength " << wavelength
-	    << " is too far from 1. Invalid material data?";
-	throw std::runtime_error(msg.str());
+        std::stringstream msg;
+        msg << "Refractive index " << n << " at wavelength " << wavelength
+            << " is too far from 1. Invalid material data?";
+        throw std::runtime_error(msg.str());
     }
 }
 
diff --git a/Sample/Multilayer/MultiLayer.cpp b/Sample/Multilayer/MultiLayer.cpp
index 96ea22af18c3640ee9a47a9fc270273052da83f8..8462da496eda3d093238ccc885b244c1a02ce3dc 100644
--- a/Sample/Multilayer/MultiLayer.cpp
+++ b/Sample/Multilayer/MultiLayer.cpp
@@ -49,7 +49,7 @@ MultiLayer* MultiLayer::clone() const
 void MultiLayer::checkMaterials(double wavelength) const
 {
     for (size_t i = 0; i < numberOfLayers(); ++i)
-	m_layers[i]->material()->checkRefractiveIndex(wavelength);
+        m_layers[i]->material()->checkRefractiveIndex(wavelength);
 }
 
 //! Adds layer with default (zero) roughness