Result indicators for each SO should refer to “sources of data”. Could you explain what it means? The value communicated at PO level will be estimations based on potential selected projects and amounts dedicated to the SO?

‘Source of data’ shall describe the organisation/institution that produced/aggregated the data for the given result indicator.
 
Explanations on the method of estimation of indicator data are among the elements that should be found in the methodological document prepared by the managing authority in accordance with the provisions of Article 13 (2) CPR.