diff --git a/src/iter/ast_node_iter.rs b/src/iter/ast_node_iter.rs
index 1c08490..1a633dd 100644
--- a/src/iter/ast_node_iter.rs
+++ b/src/iter/ast_node_iter.rs
@@ -87,64 +87,22 @@ pub enum AstNodeIter<'r, 's> {
     // Timestamp(TimestampIter<'r, 's>),
 }
 
-pub struct DocumentIter<'r, 's> {
-    zeroth_section_next: std::option::Iter<'r, Section<'s>>,
-    children_next: std::slice::Iter<'r, Heading<'s>>,
-}
-
-impl<'r, 's> Iterator for DocumentIter<'r, 's> {
-    type Item = AstNode<'r, 's>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.zeroth_section_next
-            .next()
-            .map(Into::<AstNode>::into)
-            .or_else(|| self.children_next.next().map(Into::<AstNode>::into))
-    }
-}
-
-impl<'r, 's> IntoIterator for &'r Document<'s> {
-    type Item = AstNode<'r, 's>;
-
-    type IntoIter = DocumentIter<'r, 's>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        DocumentIter {
-            zeroth_section_next: self.zeroth_section.iter(),
-            children_next: self.children.iter(),
-        }
-    }
-}
-
-pub struct HeadingIter<'r, 's> {
-    title_next: std::slice::Iter<'r, Object<'s>>,
-    children_next: std::slice::Iter<'r, DocumentElement<'s>>,
-}
-
-impl<'r, 's> Iterator for HeadingIter<'r, 's> {
-    type Item = AstNode<'r, 's>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.title_next
-            .next()
-            .map(Into::<AstNode>::into)
-            .or_else(|| self.children_next.next().map(Into::<AstNode>::into))
-    }
-}
-
-impl<'r, 's> IntoIterator for &'r Heading<'s> {
-    type Item = AstNode<'r, 's>;
-
-    type IntoIter = HeadingIter<'r, 's>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        HeadingIter {
-            title_next: self.title.iter(),
-            children_next: self.children.iter(),
-        }
-    }
-}
-
+multi_field_iter!(
+    Document<'s>,
+    DocumentIter,
+    zeroth_section,
+    std::option::Iter<'r, Section<'s>>,
+    children,
+    std::slice::Iter<'r, Heading<'s>>
+);
+multi_field_iter!(
+    Heading<'s>,
+    HeadingIter,
+    title,
+    std::slice::Iter<'r, Object<'s>>,
+    children,
+    std::slice::Iter<'r, DocumentElement<'s>>
+);
 children_iter!(Section<'s>, SectionIter, std::slice::Iter<'r, Element<'s>>);
 children_iter!(
     Paragraph<'s>,
@@ -156,7 +114,6 @@ children_iter!(
     PlainListIter,
     std::slice::Iter<'r, PlainListItem<'s>>
 );
-
 multi_field_iter!(
     PlainListItem<'s>,
     PlainListItemIter,