diff --git a/reference/SQL_MSSQL/app.h b/reference/SQL_MSSQL/app.h
index b4228e477..e3be04c54 100644
--- a/reference/SQL_MSSQL/app.h
+++ b/reference/SQL_MSSQL/app.h
@@ -6,6 +6,8 @@
 
 using namespace Upp;
 
+// debian: sudo apt-get install unixodbc-dev
+
 #include <MSSQL/MSSQL.h>
 #define SCHEMADIALECT <MSSQL/MSSQLSchema.h>
 #define MODEL <SQL_MSSQL/database.sch>
diff --git a/reference/SQL_MySql/main.cpp b/reference/SQL_MySql/main.cpp
index d451ddef8..d4ec8328a 100644
--- a/reference/SQL_MySql/main.cpp
+++ b/reference/SQL_MySql/main.cpp
@@ -1,5 +1,7 @@
 #include <MySql/MySql.h>
 
+// debian: sudo apt-get install libmysqlclient-dev
+
 using namespace Upp;
 
 #define SCHEMADIALECT <MySql/MySqlSchema.h>
diff --git a/reference/SQL_PostgreSql/Postgres.h b/reference/SQL_PostgreSql/Postgres.h
index 208fab1fd..925e6fdcf 100644
--- a/reference/SQL_PostgreSql/Postgres.h
+++ b/reference/SQL_PostgreSql/Postgres.h
@@ -14,6 +14,8 @@ using namespace Upp;
 #define MODEL <SQL_PostgreSql/database.sch>
 #include "Sql/sch_header.h"
 
+// debian: sudo apt-get install libpq-dev
+
 class PostgreSQLTest : public WithPostgreSQLTestLayout<TopWindow> {
 public:
 	typedef PostgreSQLTest CLASSNAME;