[Air-L] Citing inactive websites

Hi List, I'm revising some previous work for an upcoming book chapter and some of the websites cited in my original research no longer exist. I'd like to keep the content - mainly blog posts - as it provides context to some of my points? If I include it how should I cite it i.e. should I write 'website no longer available' or something else, and should I even include the url? Thanks in anticipation Brainstrust! Cheers Debbie McCormick