I good source that I can point to for you to reference would be Google Earth For Satellite Image Geo-referencing
Google earth is widely used, when working with geo spatial data for extracting point data and geo-referencing low resolution image . However, the accuracy of Google Earth is not defined. Our project carried out around AIT was to simply find the accuracy of, point coordinates extracted for Google Earth with DGPS coordinates. GPS observations were carried at GIC building, AIT Pool, road junctions, and basketball court as shown below. Coordinates for the Google Earth x,y columns in the following tables has be picked keeping "Eye alt ≈300m" to avoid errors in pin-pointing position on Google Earth. GPS observations has been corrected using DGPS techniques. Error in picking actual point in Google Earth has been neglected.
This shows that Google Earth is more than enough for geo-referencing low-resolution image that has 25m-30m resolution.
The accuracy of the point can be brought down to approximately 0.5m in X direction by adding -4.27m and approximately to 0.8m by adding -2.4m in y direction.
Application of this error in other areas can change due to the projection errors in Google earth.
To get a real idea of the accuracy the point extraction should be carried out covering a wide area.