Erdös number = 3
MR1325506 (96a:05116) 05C70 (05C85)
Habib, M.; Huchard, M.; Spinrad, J. A linear algorithm to decompose inheritance graphs into modules. Algorithmica 13 (1995), no. 6, 573–591.
MR902720 (88i:05117) 05C35
Spinrad, Jeremy R.; Vijayan, G.; West, Douglas B. An improved edge bound on the interval number of a graph. J. Graph Theory 11 (1987), no. 3, 447–449.
MR798529 (86k:05062) 05C35 (05C80)
Erdős, Paul; West, Douglas B. A note on the interval number of a graph. Discrete Math. 55 (1985), no. 2, 129–133.