Bulgaria
Schafferer, C., Yeh, C.Y., Chen, S.H. 2018
Gallagher, A.W.A., Evans-Reeves, K.A., Hatchard, J.L. et al. 2018
Filippidis, F.T., Laverty, A.A., Hone, T. et al. 2017
European Commission 2015
Pederson, H., Floristean, A., Iseppi, L. et al. 2014
Skafida, V., Silver, K.E., Rechel, B.P.D. et al. 2014
Gallus, S., Lugo, A., La Vecchia, C. et al. 2012
European Commission 2009
Gallus, S., Schiaffino, A., La Vecchia, C. et al. 2006
Gallus, S., Schiaffino, A., La Vecchia, C. et al. 2006
Petkova, R., Ileva, R., Rusenov, A. 2003