Myriads of protein families, and still counting.

Citation
Kunin, V., Cases, I., Enright, A. J., de Lorenzo, V., & Ouzounis, C. A. (2003). Genome Biology, 4(2), 401. https://doi.org/10.1186/gb-2003-4-2-401
DOI:
DOI: 10.1186/gb-2003-4-2-401
Year of publication:
2003