Lee, J.K., & Calandra, B. (2004). Can Embedded Annotations Help High-School Students Perform Problem Solving Tasks Using A Web-Based Historical Document? Journal of Research on Technology in Education, 37:1, 65-84.
"Authentic resources for social studies and history are widely available online, but most of these resources do not take advantage of the unique hypermedia capabilities of the Web."
The authors describe their research which involved students groups located at two different high schools. One group was used as a control while the other had access to the same online primary source material (the US Constitution) but with topical annotations added to the site in order to aid student understanding. The students had the same investigative task, and the group that had the annotations performed better with the scaffold supports.