Volumes 133-140 of the Series II in years 1964 and 1965 were split into issues A and B. Later they were unified into a single series again.[3] They are different from Phys. Rev. A and B of the third series. For example "Phys. Rev. 133 A1 (1964)" is an article of Ser. II, while "Phys. Rev. A 1 1 (1970) is of Phys. Rev. A.