diff --git a/qad/doc/CMakeLists.txt b/qad/doc/CMakeLists.txt
index 986dbfc..5bd3a86 100644
--- a/qad/doc/CMakeLists.txt
+++ b/qad/doc/CMakeLists.txt
@@ -12,5 +12,6 @@ if (MARKDOWN_HEADER_MARKDOWN)
 	add_definitions("-DMARKDOWN_HEADER=\"markdown/markdown.h\"")
 endif()
 find_library(MARKDOWN_LIBRARY markdown)
-
-qad_project(doc "Core" ${MARKDOWN_LIBRARY})
+if (MARKDOWN_LIBRARY)
+	qad_project(doc "Core" "${MARKDOWN_LIBRARY}")
+endif()