Complex sentence: Klempner's articles have appeared internationally in professional publications such as "The Oral History Reader", and he has been a guest columnist for mainstream periodicals such as the "National Catholic Reporter" and the "Raleigh News and Observer".
Split into simpler sentences: Klempner's articles have appeared internationally in professional publications such as "The Oral History Reader". He has also been a guest columnist for mainstream periodicals such as the "National Catholic Reporter" and the "Raleigh News and Observer".