anchor.diff:      <<"http://creativecommons.org/publicdomain/mark/1.0">>;
   url_for(_) ->
       undefined.
  +
  +%% @doc Get URL to translated license at the Creative Commons website
  +-spec language_url_for(binary(), #context{}) -> binary() | undefined.
  +language_url_for(License, Context) ->
  +    with_language(url_for(License), Context).
  +
  +-spec with_language(binary() | undefined, #context{}) -> binary() | undefined.
  +with_language(undefined, _Context) ->
  +    undefined;
  +with_language(Url, Context) ->
  +    iolist_to_binary([
  +        Url,
  +        <<"/deed.">>,
  +        z_convert:to_binary(z_context:language(Context))
  +    ]).
  
positive.code:     m_find_value/3,
      m_to_list/2,
      m_value/2,
      url_for/1
  ]).
  
  -include_lib("zotonic.hrl").
  
negative.code: m_value(_Source, _Context) ->
      undefined.
  
  %% @doc Get URL to license at the Creative Commons website
  -spec url_for(binary() | string()) -> binary() | undefined.
  url_for(License) when is_list(License) ->
      url_for(z_convert:to_binary(License));
  url_for(<<"BY">>) ->
  