Undefined index notice in agenda results

For some of the events in the agenda not all location data has been filled in, resulting in the following notice in the overview:

> Notice: Undefined index: city in include() (line 40 of sites/all/modules/contrib/culturefeed/culturefeed_agenda/theme/culturefeed-event-summary.tpl.php).

And these in the detail page:

> Notice: Undefined index: street in include() (line 38 of sites/all/modules/contrib/culturefeed/culturefeed_agenda/theme/culturefeed-event.tpl.php).
> Notice: Undefined index: zip in include() (line 38 of sites/all/modules/contrib/culturefeed/culturefeed_agenda/theme/culturefeed-event.tpl.php).
> Notice: Undefined index: city in include() (line 38 of sites/all/modules/contrib/culturefeed/culturefeed_agenda/theme/culturefeed-event.tpl.php).