1. Seasonal ground-water level changes (1990-93) and flow patterns in the Fristoe unit of the Mark Twain National Forest, southern Missouri Yale Public content 1995. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; Earth Science Information Center, Open-File Reports Section, distributor. English. Public. Missouri and Mark Twain National Forest.