diff --git a/nselib/pop3.lua b/nselib/pop3.lua
index 5eaf5d1d0..e820e2d8e 100644
--- a/nselib/pop3.lua
+++ b/nselib/pop3.lua
@@ -138,7 +138,9 @@ function login_apop(socket, user, pw, challenge)
 end
 
 ---
--- Asks a POP3 server for capabilities
+-- Asks a POP3 server for capabilities.
+--
+-- See RFC 2449.
 -- @param host Host to be queried.
 -- @param port Port to connect to.
 -- @return Table containing capabilities.
diff --git a/scripts/pop3-capabilities.nse b/scripts/pop3-capabilities.nse
index a54127e71..9cfbe5b38 100644
--- a/scripts/pop3-capabilities.nse
+++ b/scripts/pop3-capabilities.nse
@@ -1,5 +1,10 @@
 description = [[
 Retrieves POP3 email server capabilities.
+
+POP3 capabilities are defined in RFC 2449. The CAPA command allows a client to
+ask a server what commands it supports and possibly any site-specific policy.
+Besides the list of supported commands, the IMPLEMENTATION string giving the
+server version may be available.
 ]]
 
 ---