Complex sentence: Fictitious entries, also known as fake entries, Mountweazels, and Nihilartikels, are deliberately incorrect entries or articles in reference works such as dictionaries, encyclopedias, maps and directorle external source, but no such source exists for a fictitious entry.
Split into simpler sentences: Fictitious entries, also known as fake entries, Mountweazels, and Nihilartikels, are deliberately incorrect entries or articles in reference works such as dictionaries, encyclopedias, maps and directories. Entries in reference works normally originate from a reliable external source, but no such source exists for a fictitious entry.