@article{DostalFennelKochetal.2018,
  author    = {Jakub Dost{\´a}l and Franziska Fennel and Federico Koch and Stefanie Herbst and Frank W{\"u}rthner and Tobias Brixner},
  title     = {Direct observation of exciton-exciton interactions},
  journal   = {Nature Communications},
  volume    = {9},
  doi       = {10.1038/s41467-018-04884-4},
  year      = {2018},
}