What has the author Mary Lou Dettmer written?

Mary Belle Lontz has written:

'The Berkheimer family in Pa., Va., W. Va., and other States'

'Revolutionary War soldiers of Union County, Pennsylvania' -- subject(s): Registers, Militia, Genealogy, History

'Civil War soldiers of Union County, Pennsylvania' -- subject(s): Genealogy, History, Pennsylvania Civil War, 1861-1865, Registers, Soldiers, United States Civil War, 1861-1865

'History of the schools of Union County, Pennsylvania' -- subject(s): Alumni and alumnae, Public schools, Directories, Rural schools, History

'Boulder Dam builders' -- subject(s): Registers, Genealogy

'The Noll family' -- subject(s): Genealogy

'Union County, Pennsylvania, 1855-1965' -- subject(s): Genealogy, History

'Union County, Pennsylvania census of 1850' -- subject(s): Census, 1850, Registers of births, Genealogy, Census, 7th, 1850