BPMN21 — Cardinality of sources for Data Association

Throughout the text it is stated that a data association has one or more sources and one target (see page 228). First of all, if that is true the meta-model should be adjusted on page 229, figure 10.64. Taking "" as cardinality for sources of a data association would allow a data association to exist without any source. I suggest to change the cardinality to "1..".

Second, in the description I couldn't find any example explaining for which cases more than one source in a data association makes sense. Is it allowed because a data object can be collection?