diff --git a/GRAMMAR.md b/GRAMMAR.md
index 3bceece..231d8d1 100644
--- a/GRAMMAR.md
+++ b/GRAMMAR.md
@@ -45,6 +45,7 @@ export        : 'export' assignment
 expression    : STRING
               | RAW_STRING
               | NAME
+              | BACKTICK
               | expression '+' expression
 
 recipe        : NAME arguments? ':' dependencies? body?