diff --git a/src/feed/atom.go b/src/feed/atom.go
index 3e966f7..fae3b86 100644
--- a/src/feed/atom.go
+++ b/src/feed/atom.go
@@ -1,3 +1,4 @@
+// Atom 1.0 parser
 package feed
 
 import (
diff --git a/src/feed/json.go b/src/feed/json.go
index f4049d7..71286be 100644
--- a/src/feed/json.go
+++ b/src/feed/json.go
@@ -1,3 +1,4 @@
+// JSON 1.0 parser
 package feed
 
 import (
diff --git a/src/feed/rdf.go b/src/feed/rdf.go
index cdd2f0d..21cd36a 100644
--- a/src/feed/rdf.go
+++ b/src/feed/rdf.go
@@ -1,3 +1,6 @@
+// Parser for RSS versions:
+// - 0.90
+// - 1.0
 package feed
 
 import (
diff --git a/src/feed/rss.go b/src/feed/rss.go
index 754223d..ba1ab75 100644
--- a/src/feed/rss.go
+++ b/src/feed/rss.go
@@ -1,3 +1,7 @@
+// Parser for RSS versions:
+// - 0.91 netscape
+// - 0.91 userland
+// - 2.0
 package feed
 
 import (