diff --git a/Syntax.md b/Syntax.md
index ad4ddd6..4c1eb3e 100644
--- a/Syntax.md
+++ b/Syntax.md
@@ -446,8 +446,11 @@ citation to the references, but does not show up in the document as a citation.
 The first seen modifier determines the type (suppressed, normative or informative).
 Multiple citation can separated with a semicolon: `[@RFC1034; @RFC1035]`.
 
-If you reference an RFC or I-D the reference will be added automatically (no need to muck about
-with an `<reference>` block.
+If you reference an RFC, I-D or W3C document the reference will be added automatically (no need to
+muck about with an `<reference>` block. This is to say:
+
+Any reference starting with *RFC*, *I-D.* or *W3C.* will be automatically added to the correct
+reference section.
 
 For I-Ds you may want to add a draft sequence number, which can be done as such: `[@?I-D.blah#06]`.
 If you reference an I-D *without* a sequence number it will create a reference to the *last* I-D in
diff --git a/xml/bibliography.go b/xml/bibliography.go
index 58260ea..b9392c4 100644
--- a/xml/bibliography.go
+++ b/xml/bibliography.go
@@ -39,7 +39,10 @@ func (r *Renderer) bibliographyItem(w io.Writer, node *mast.BibliographyItem) {
 	tag := ""
 	switch {
 	case bytes.HasPrefix(node.Anchor, []byte("RFC")):
-		tag = makeXiInclude(toolsIetfOrg, fmt.Sprintf("reference.RFC.%s.xml", node.Anchor[3:]))
+		tag = makeXiInclude(ToolsRFC, fmt.Sprintf("reference.RFC.%s.xml", node.Anchor[3:]))
+
+	case bytes.HasPrefix(node.Anchor, []byte("W3C.")):
+		tag = makeXiInclude(ToolsW3C, fmt.Sprintf("reference.RFC.%s.xml", node.Anchor[3:]))
 
 	case bytes.HasPrefix(node.Anchor, []byte("I-D.")):
 		hash := bytes.Index(node.Anchor, []byte("#"))
@@ -48,7 +51,7 @@ func (r *Renderer) bibliographyItem(w io.Writer, node *mast.BibliographyItem) {
 			node.Anchor[hash] = '-'
 			defer func() { node.Anchor[hash] = '#' }() // never know if this will be used again
 		}
-		tag = makeXiInclude(toolsIetfOrg, fmt.Sprintf("reference.I-D.draft-%s.xml", node.Anchor[4:]))
+		tag = makeXiInclude(ToolsID, fmt.Sprintf("reference.I-D.draft-%s.xml", node.Anchor[4:]))
 	}
 	r.outs(w, tag)
 	r.cr(w)
@@ -59,4 +62,8 @@ func makeXiInclude(url, reference string) string {
 	return fmt.Sprintf("<xi:include href=\"%s/%s\"/>", url, reference)
 }
 
-var toolsIetfOrg = "https://xml2rfc.tools.ietf.org/public/rfc/bibxml"
+var (
+	ToolsRFC = "https://xml2rfc.ietf.org/public/rfc/bibxml/"
+	ToolsID  = "https://xml2rfc.ietf.org/public/rfc/bibxml-ids/"
+	ToolsW3C = "https://xml2rfc.ietf.org/public/rfc/bibxml-w3c/"
+)
diff --git a/xml2/bibliography.go b/xml2/bibliography.go
index 4400395..6615a1a 100644
--- a/xml2/bibliography.go
+++ b/xml2/bibliography.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/gomarkdown/markdown/ast"
 	"github.com/mmarkdown/mmark/mast"
+	"github.com/mmarkdown/mmark/xml"
 )
 
 func (r *Renderer) bibliography(w io.Writer, node *mast.Bibliography, entering bool) {
@@ -40,7 +41,11 @@ func (r *Renderer) bibliographyItem(w io.Writer, node *mast.BibliographyItem) {
 	tag := ""
 	switch {
 	case bytes.HasPrefix(node.Anchor, []byte("RFC")):
-		tag = makeRFCInclude(toolsIetfOrg, fmt.Sprintf("reference.RFC.%s.xml", node.Anchor[3:]))
+		tag = makeRFCInclude(xml.ToolsRFC, fmt.Sprintf("reference.RFC.%s.xml", node.Anchor[3:]))
+
+	case bytes.HasPrefix(node.Anchor, []byte("W3C.")):
+		tag = makeRFCInclude(xml.ToolsW3C, fmt.Sprintf("reference.RFC.%s.xml", node.Anchor[3:]))
+
 	case bytes.HasPrefix(node.Anchor, []byte("I-D.")):
 		hash := bytes.Index(node.Anchor, []byte("#"))
 		if hash > 0 {
@@ -48,7 +53,7 @@ func (r *Renderer) bibliographyItem(w io.Writer, node *mast.BibliographyItem) {
 			node.Anchor[hash] = '-'
 			defer func() { node.Anchor[hash] = '#' }() // never know if this will be used again
 		}
-		tag = makeRFCInclude(toolsIetfOrg, fmt.Sprintf("reference.I-D.draft-%s.xml", node.Anchor[4:]))
+		tag = makeRFCInclude(xml.ToolsID, fmt.Sprintf("reference.I-D.draft-%s.xml", node.Anchor[4:]))
 	}
 	r.outs(w, tag)
 	r.cr(w)
@@ -57,5 +62,3 @@ func (r *Renderer) bibliographyItem(w io.Writer, node *mast.BibliographyItem) {
 func makeRFCInclude(url, reference string) string {
 	return fmt.Sprintf("<?rfc include=\"%s/%s\"?>", url, reference)
 }
-
-var toolsIetfOrg = "https://xml2rfc.tools.ietf.org/public/rfc/bibxml"