title: Space-filling molecular models of four-membered rings. Three-dimensional aspects in the design of penicillin and cephalosporin antibiotics.
mesh_terms: D002511:Cephalosporins; D055598:Chemical Phenomena; D002621:Chemistry; D007769:Lactams; D008961:Models, Structural; D010406:Penicillins
chemical_list: D002511:Cephalosporins; D007769:Lactams; D010406:Penicillins