title = "How much research output is really open, and how can we tell?",
author = "Esther Plomp and Meron Vermaas and Carlos Martinez-Ortiz and Nemo Andrea and Ewan Cahen and Felix Weijdema and Dorien Huijser and Marta Teperek and Bj{\o}rn Bartholdy and Caba{\~n}ero, \{Ana Parr{\'o}n\}",