@article{article, title = {{Spectral classification of O2-3.5If/WN5-7 stars}}, url = {{http://eprints.whiterose.ac.uk/123510/ }}, year = {{2011}}, month = {{1}}, author = {{Crowther PA and Walborn NR}}, doi = {{10.1111/j.1365-2966.2011.19129.x}}, volume = {{416}}, journal = {{Monthly Notices of the Royal Astronomical Society}}, issue = {{2}}, pages = {{1311-1323}}, note = {{Accessed on 2024/12/22}}}