I have seen this kind of question many times. Normally, if the data are collected/organized by some private firms and person A has the access to this data, you need to co-author with the data providers in order to get the data. Otherwise, the firms may question your data sources. If the data are collected personally and that person might be glad to share the data with you FOR FREE, you are fine.
【在 s***r 的大作中提到】 : I have seen this kind of question many times. : Normally, if the data are collected/organized by some private firms and : person A has the access to this data, you need to co-author with the data : providers in order to get the data. Otherwise, the firms may question your : data sources. : If the data are collected personally and that person might be glad to share : the data with you FOR FREE, you are fine.