diff --git a/doc/formats.md b/doc/formats.md
index ac5ccb8..36f8a73 100644
--- a/doc/formats.md
+++ b/doc/formats.md
@@ -56,7 +56,6 @@ Processed source is scanned for known keys. Known keys are:
 * nick
 * name
 * mail
-* phone
 * born
 
 Multiple instances of single key are considered an error.
@@ -83,6 +82,7 @@ line numbers as the value for such key. Multikeys are:
 * revisionstop
 * grantstart
 * grantstop
+* phone
 
 The result is a valid dictionary of keys and multikeys.
 
@@ -104,7 +104,8 @@ periods.
 The joined key is converted into a month value.
 
 Card and desfire lists are parsed to get lists of card id and optional
-comment.
+comment. The same processing is used for phone to support multiple
+phone numbers.
 
 Credit list is parsed to get a list of amounts and optional comments.