I think I may have found them for you. The Maple Grove Cemetery in Yankton County seems to fit the description also. Here is the link from USGENweb.com
http://ftp.rootsweb.com/pub/usgenweb/sd/yankton/cemeteries/m...It has three Jensen Children and a Mr. and Mrs. Jensen. Unfortunately the WPA was unable to read a whole lot more than this. Sincerely, Carrie Taylor