Sorry I missed this earlier. Here are some books that you may find useful:

GENERAL

• Southeastern Ceremonial Complex: Chronology, Content, Context, ed. Adam King
• Mississippian Communities and Households, ed. J. Daniel Rogers
• Temples and Towns Along the Mississippi, ed. David H. Dye and Cheryl Anne Cox
• Archaeology of the Soul: North American Indian Belief and Ritual, Robert Hall (not primarily concerned with Mississippians, but touches on the topic enough to be worth checking out)
• Knights of Spain, Warriors of the Sun: Hernando de Soto and the South's Ancient Chiefdoms, Charles Hudson (Mainly about the mid-1500s, but a very useful synthesis of archaeology and history to give you an idea of what Mississippian polities were like)

SPECIFIC MISSISSIPPIANS

• Ancient Cahokia and the Mississippians, Timothy Pauketat
• Etowah: the Political History of a Chiefdom Capital, Adam King
• Coosa: the Rise and Fall of a Southeastern Mississippian Chiefdom, Marvin T. Smith (Coosa's a bit later than you want, but it's an interesting follow up to Etowah)
• Archaeology of the Moundville Chiefdom: Chronology, Content, Contest, Vernon Knight
• The Archaeology of Everyday Life at Early Moundville, Gregory D. Wilson
• Bottle Creek: A Pensacola Culture Site in South Alabama, Ian Brown

Can you please be more specific in terms of geographical area?

Woodland culture spread all the way up into ontario and might have been instrumental in bringing corn to the area. On other hand, you might be thinking of the cahokia area. Hard to give you info on which sources to read up on when its that broad