diff --git a/entry.go b/entry.go
index 0cb2690..744e5ab 100644
--- a/entry.go
+++ b/entry.go
@@ -6,6 +6,10 @@ import (
 	"fmt"
 )
 
+// It is advisable that each atom:entry element contain a non-empty atom:title
+// element, a non-empty atom:content element when that element is present, and
+// a non-empty atom:summary element when the entry contains no atom:content
+// element.
 type Entry struct {
 	*CommonAttributes
 	Authors      []*Person           `xml:"author,omitempty"`
diff --git a/feed.go b/feed.go
index c24d843..961f421 100644
--- a/feed.go
+++ b/feed.go
@@ -26,9 +26,9 @@ type Feed struct {
 	Entries      []*Entry            `xml:"entry,omitempty"`
 }
 
-// atom:feed elements MUST NOT contain more than one atom:link
-// element with a rel attribute value of "alternate" that has the
-// same combination of type and hreflang attribute values.
+// atom:feed elements MUST NOT contain more than one atom:link element with a
+// rel attribute value of "alternate" that has the same combination of type and
+// hreflang attribute values.
 func hasAlternateDuplicateLinks(l []*Link) bool {
 	linkMap := make(map[string]bool)