1. Laboratory of Molecular Biology and Viral Oncogenesis, Istituto Nazionale Tumori Fond. G. Pascale, Naples, Italy
2. Bioqual Inc., Rockville, Maryland, USA
3. Advanced BioScience Laboratories, Inc., Kensington, Maryland, USA
4. Eurocine Vaccines AB, Karolinska Institutet Science Park, Stockholm, Sweden
5. Department of Molecular Virology, Linköping University, Linköping, Sweden
6. Swedish Institute for Infectious Disease Control, Stockholm, Sweden