diff --git a/image-layout.md b/image-layout.md
index b49190512..c02e806e9 100644
--- a/image-layout.md
+++ b/image-layout.md
@@ -58,7 +58,7 @@ A blob, referenced with digest `<alg>:<hex>` (per [descriptor](descriptor.md#dig
 The character set of the entry name for `<hex>` and `<alg>` MUST match the respective grammar elements described in [descriptor](descriptor.md#digests-and-verification).
 For example `sha256:5b` will map to the layout `blobs/sha256/5b`.
 
-The blobs directory MAY contain blobs which are not referenced by any of the refs.
+The blobs directory MAY contain blobs which are not referenced by any of the [refs](#indexjson-file).
 
 The blobs directory MAY be missing referenced blobs, in which case the missing blobs SHOULD be fulfilled by an external blob store.
 
diff --git a/specs-go/v1/layout.go b/specs-go/v1/layout.go
index b3a9fb134..c1c7a7870 100644
--- a/specs-go/v1/layout.go
+++ b/specs-go/v1/layout.go
@@ -14,8 +14,6 @@
 
 package v1
 
-import "regexp"
-
 // ImageLayoutVersion is the version of ImageLayout
 const ImageLayoutVersion = "1.0.0"
 
@@ -24,8 +22,3 @@ const ImageLayoutVersion = "1.0.0"
 type ImageLayout struct {
 	Version string `json:"imageLayoutVersion"`
 }
-
-var (
-	// RefsRegexp matches requirement of image-layout 'refs' charset.
-	RefsRegexp = regexp.MustCompile(`^[a-zA-Z0-9-._]+$`)
-)