@article{Hillen1981,
  author    = {Hillen, Walter},
  title     = {\&\#923;, Image production in e+e- annihilation at 33 GeV centre of mass energy. TASSO Collaboration},
  series = {Physics Letters B. 105 (1981), H. 4},
  journal   = {Physics Letters B. 105 (1981), H. 4},
  isbn      = {0370-2693},
  pages     = {75 -- 80},
  year      = {1981},
  language  = {en}
}
@article{Hillen1981,
  author    = {Hillen, Walter},
  title     = {Evidence for charged primary partons in e+e\&\#8722; \&\#8594; 2 jets. TASSO Collaboration},
  series = {Physics Letters B. 100 (1981), H. 4},
  journal   = {Physics Letters B. 100 (1981), H. 4},
  isbn      = {0370-2693},
  pages     = {357 -- 363},
  year      = {1981},
  language  = {en}
}
@article{Hillen1981,
  author    = {Hillen, Walter},
  title     = {Search for new sequential leptons in e+e- annihilation at petra energies. TASSO Collaboration},
  series = {Physics Letters B. 99 (1981), H. 2},
  journal   = {Physics Letters B. 99 (1981), H. 2},
  isbn      = {0370-2693},
  pages     = {163 -- 168},
  year      = {1981},
  language  = {en}
}