François Haverschmidt (1835-1894) used the pen name Piet Paaltjens for the poetry he wrote as an undergraduate. His prose works were published under his real name. Current scholarship attributes the "Oera Linda book" to this author. This is not beyond all doubt though.
His grandson, also called François Haverschmidt (1906-1987) - but who did not use the alias Piet Paaltjens - wrote books on the birds of Surinam.