diff --git a/How-to-build.md b/How-to-build.md
index 3acd893..4a4ef7f 100644
--- a/How-to-build.md
+++ b/How-to-build.md
@@ -15,7 +15,7 @@ These libraries are automatically added/resolved per NuGet:
 * Ionic.Zip.dll
 * log4net.dll
 
-(Only for testing purposes) you also need NUnit libraries:
+(Only for testing purposes) you also need NUnit libraries which can be obtained from http://www.nunit.org:
 
 * nunit.framework.dll
 * Moq.dll