Rack, M., Sieglin, B., Eich, T., Pearson, J., Liang, Y., Balboa, I., et al. (2014). Findings of pre-ELM structures through the observation of divertor heat load patterns at JET with applied n=2 perturbation fields (Letter). Nuclear Fusion, 54: 072004. doi:10.1088/0029-5515/54/7/072004.