Warren A J, Warren W D, Cox E C
Proc Natl Acad Sci U S A. 1975 Mar;72(3):1041-2. doi: 10.1073/pnas.72.3.1041.
Complementation tests were performed between pairs of independently isolated aggregation defective mutants of P. violaceum. Analysis of the results suggests that the approximate number of genes controlling aggregation in this organism is 50.