That would depend on where you live. If you live in Mississippi you can use the link I provided and order by email.If you live outside Mississippi, you have to send a written request to the address provided. The charge is $15.00 for I hours resarch time, non-refundable.
If you live outside Mississippi, I suggest ordering from this site.
My understandis that either of the above methods is better than the NARA.
Here is the link to MDAH
http://www.mdah.state.ms.us/arlib/contents/arlib_refrules.html
george