Acknowledging data sources used for creating an image For a conference paper, I created an image compiling data from multiple sources. What is the correct format for acknowledging the sources?

Map showing road condition (Data source: Esri, OpenStreetMap) or,

Map showing road condition (Data sources: Esri, OpenStreetMap)

In most of the literature, I observed authors commonly using 'source' when they mean 'sources'. Shouldn't it be 'sources'?
As others have pointed out, the choice is likely arbitrary since it will not affect the readability of your article much.

If you want to keep the formulation as is, I would personally go with "Data sources" as I think it makes more linguistic sense. If I would ask the reader to check out two published articles, I would write: "see the papers by Uncle Tom Cobley (1889) and Alan Smithee (1968)" and not "see the paper by Uncle Tom Cobley (1889) and Alan Smithee (1968).". Similarly, I would write "see the data sources Esri and OpenStreetMap" and not "see the data source Esri and OpenStreetMap".

However, one possible workaround would be to side-step the issue by chosing a different formulation. For instance, perhaps by writing "Data from",  or just simply "Data".