2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2002 1979 Atomically thin hexagonal boron nitride probed by ultrahigh-resolution transmission electron microscopy N Alem, R Erni, C Kisielowski, MD Rossell, W Gannett, A Zettl Physical Review B 80 (15), 155425 582 2009