Mazzarello, P (1999). "A unifying concept: the history of cell theory". Nature Cell Biology1: E13–E15. doi:10.1038/8964.
Whittaker, R.H. (January 1969). "New concepts of kingdoms or organisms. Evolutionary relations are better represented by new classifications than by the traditional two kingdoms". Science163 (3863): 150–60. Bibcode1969Sci...163..150W. doi:10.1126/science.163.3863.150.
Mora, Camilo; Tittensor, Derek P.; Adl, Sina; Simpson, Alastair G. B.; Worm, Boris; Mace, Georgina M. (23 August 2011). "How Many Species Are There on Earth and in the Ocean?". PLOS Biology9 (8): e1001127. doi:10.1371/journal.pbio.1001127. PMC3160336.
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Whittaker, R.H. (January 1969). "New concepts of kingdoms or organisms. Evolutionary relations are better represented by new classifications than by the traditional two kingdoms". Science163 (3863): 150–60. Bibcode1969Sci...163..150W. doi:10.1126/science.163.3863.150.
Mora, Camilo; Tittensor, Derek P.; Adl, Sina; Simpson, Alastair G. B.; Worm, Boris; Mace, Georgina M. (23 August 2011). "How Many Species Are There on Earth and in the Ocean?". PLOS Biology9 (8): e1001127. doi:10.1371/journal.pbio.1001127. PMC3160336.