00/416 - MAPREC assay of poliovirus type 1 (Sabin) Low Mutant Virus Reference(1st International Reference Preparation) 00/418 - MAPREC assay of poliovirus type 1 (Sabin) (1st International Standard) 00/422 - MAPREC assay of poliovirus type 1 High(Sabin) Mutant Virus Reference(1st International Reference Preparation)