Complex sentence: Yockelson is considered one of the foremost authorities on the topic of World War I. Currently he teaches at Norwich University, and works as an Investigative Archivist at the National Archives and Records Administration.
Split into simpler sentences: Yockelson is considered one of the foremost authorities on the topic of World War I. Currently he teaches at Norwich University. He also works as an Investigative Archivist at the National Archives and Records Administration.