The length of a tetranucleotide repeat tract in Haemophilus influenzae determines the phase variation rate of a gene with homology to type III DNA methyltransferases (vol 35, pg 211, 2000) - De Bolle, X; Bayliss, C; Field, D; van de Ven, T; Saunders, N; Hood, D; Moxon, E (2002)