anchor.diff:  			query_page1(PageServer, Etag, fun usage_aaa_acct/2, Filters, Start, End);
   		{_, {_, "PublicWLANAccessUsage"}, []} ->
   			{error, 404}; % todo?
  +		{_, {_, "HTTPUsageTransfer"}, []} ->
  +			query_page1(PageServer, Etag, fun usage_http_transfer/2, Filters, Start, End);
   		{_, {_, _}, []} ->
   			{error, 404};
   		{_, {_, _}, _} ->
  
positive.code: 			end;
  		{_, {_, "PublicWLANAccessUsage"}, []} ->
  			{error, 404}; % todo?
  		{_, {_, _}, []} ->
  			{error, 404};
  		{_, {_, _}, _} ->
  
negative.code: 	lists:reverse(Acc).
  
  %% @hidden
  usage_http_transfer({Host, User, DateTime, Method, URI, HttpStatus}, Filters) ->
  	UsageSpec = {struct, [{"id", "HTTPUsageTransferSpec"},
  			{"href", "/usageManagement/v1/usageSpecification/HTTPUsageTransferSpec"},
  			{"name", "HTTPUsageTransferSpec"}]},
  	Type = "HTTPUsageTransfer",
  	Status = "?",
  	ID = "http-",
  	Href = "/usageManagement/v1/usage/" ++ ID,
  	UsageChars = [{struct, [{"name", "datetime"}, {"value", DateTime}]},
  			{struct, [{"name", "host"}, {"value", Host}]},
  			{struct, [{"name", "user"}, {"value", User}]},
  			{struct, [{"name", "method"}, {"value", Method}]},
  			{struct, [{"name", "uri"}, {"value", URI}]},
  			{struct, [{"name", "httpStatus"}, {"value", HttpStatus}]}],
  	Object = {struct, [{"id", ID}, {"href", Href}, {"date", "?"}, {"type", Type},
  			{"status", Status}, {"usageSpecification", UsageSpec},
  			{"usageCharacteristic", {array, UsageChars}}]},
  	if
  		Filters =:= [] ->
  			Object;
  		true ->
  			ocs_rest:filter("id,href," ++ Filters, Object)
  	end;
  usage_http_transfer(Events, Filters) when is_list(Events) ->
  	usage_http_transfer(Events, Filters, []).
  %% @hidden
  usage_http_transfer([H | T], Filters, Acc) ->
  	usage_http_transfer(T, Filters, [usage_http_transfer(H, Filters) | Acc]);
  usage_http_transfer([], _Filters, Acc) ->
  	lists:reverse(Acc).
  
  %% @hidden
  spec_aaa_auth() ->
  	ID = {"id", "AAAAccessUsageSpec"},
  	Href = {"href", "/usageManagement/v1/usageSpecification/AAAAccessUsageSpec"},
  