I've seen references to - but am having trouble finding concrete research on - the typical lifecycle of flu pandemics. Eyeballing case counts in the UK/US, 1918 and 2009 both had two waves of 4-8 weeks each. Both the relatively short duration of each wave and the likelihood of a second wave seem like Very Important Things To Know, but I'd like something to cite before shooting my mouth off. Have you come across any good resources on this?
The best paper I've found so far is this review of the two 2009 waves in the US , but I'd really like something that compares pandemic lifecycles across time and across countries.