title: [Population heterogeneity of modern influenza B virus strains].
mesh_terms: D000818:Animals; D002500:Centrifugation, Isopycnic; D002501:Centrifugation, Zonal; D002642:Chick Embryo; D008854:Microscopy, Electron; D009975:Orthomyxoviridae / Q000302:isolation & purification* / Q000648:ultrastructure; D014586:USSR; D014776:Virus Cultivation
vernacular_title: Geterogennost' populiatsiĭ sovremennykh shtammov virusa grippa B