I'm sorry, electronic access to this journal article does not appear to be available. However, your interlibrary loan program may well be able to get a .PDF copy to you within a couple days. See Bryn Mawr interlibrary loan for more information.
The Worldcat (OCLC) library catalog gives the magazine 297 holding libraries worldwide, but none in PA, unfortunately. If you do interlibrary loan, be sure to give ISSN 0028-1859.
Also, here's is an online version of "The Medals of Wounded Knee" by Jerry Green.
Unfortunately, it is impossible to tell if this is the same article that appeared in Nebraska History. There is an email on the page that claims to be the author's; you may also consider contacting him directly.
Thanks,
Terry