Current Opinion in Structural Biology. Nature Reviews. Molecular Cell Biology. Nature. 178 (4541): 1020-3. Bibcode:1956Natur.178.1020F. In 2002, a trademark dispute with the nonprofit World Wide Fund for Nature expected the firm to settle on the existing initialism. Nature. 560 (7718): 331-335. Bibcode:2018Natur.560..331S. Pereira SL, Grayling RA, Lurz R, Reeve JN (November 1997). "Archaeal nucleosomes". Sandman K, Reeve JN (March 2000).