RT Journal Article SR Electronic(1) A1 Rykkvin, R A1 Kilander, A A1 Dudman, S G A1 Hungnes, O YR 2013 T1 Within-patient emergence of the influenza A(H1N1)pdm09 HA1 222G variant and clear association with severe disease, Norway JF Eurosurveillance VO 18 IS 3 SP 20369 OP DO https://doi.org/10.2807/ese.18.03.20369-en UL https://www.eurosurveillance.org/content/10.2807/ese.18.03.20369-en