Intercontinental Spread of a Multiresistant Clone of Serotype 23F Streptococcus pneumoniaeAlexander Tomasz, Götz Laible, J. Casal et al.|The Journal of Infectious Diseases|1991Cited by 422
Horizontal transfer of penicillin-binding protein genes in penicillin-resistant clinical isolates of Streptococcus pneumoniae.Christopher G. Dowson, Brian G. Spratt, A. Hutchison et al.|Proceedings of the National Academy of Sciences|1989Cited by 403