TY - JOUR T1 - Spectral classification of O2-3.5If/WN5-7 stars JO - Monthly Notices of the Royal Astronomical Society UR - http://eprints.whiterose.ac.uk/123510/ PY - 2011/01/01 AU - Crowther PA AU - Walborn NR ED - DO - DOI: 10.1111/j.1365-2966.2011.19129.x VL - 416 IS - 2 SP - 1311 EP - 1323 Y2 - 2024/12/22 ER -