diff --git a/Number_types/doc/Number_types/Doxyfile.in b/Number_types/doc/Number_types/Doxyfile.in
index 7a5e80e121f..4086ff6b199 100644
--- a/Number_types/doc/Number_types/Doxyfile.in
+++ b/Number_types/doc/Number_types/Doxyfile.in
@@ -2,6 +2,8 @@
 
 PROJECT_NAME = "CGAL ${CGAL_DOC_VERSION} - Number Types"
 INPUT += ${CGAL_PACKAGE_INCLUDE_DIR}/CGAL/Exact_integer.h \
-         ${CGAL_PACKAGE_INCLUDE_DIR}/CGAL/Exact_rational.h
+         ${CGAL_PACKAGE_INCLUDE_DIR}/CGAL/Exact_rational.h \
+         ${CGAL_PACKAGE_INCLUDE_DIR}/CGAL/Zp.h \
+         ${CGAL_PACKAGE_INCLUDE_DIR}/CGAL/Z2.h
 
 SHOW_FILES = YES