Virologists classify both A and B viruses according to their place of origin, the isolate number and the date the strain was first identified. They classify A viruses further, by their H and N protein make-up, for instance A (H3N2). An example of classification of a Type A strain would be A/sydney/5/97 (H3N2), a recent strain. The notorious Spanish flu of 1918 has been identified as A (H1N1), but Spain was simply the country that first published reports of the spreading pandemic.⁸⁸