no. 1
A simplified proof of the Sevastyanov theorem on branching processes
Annales de l'I.H.P. Probabilités et statistiques, Tome 6 (1970) no. 1, pp. 1-7. 
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     author = {Jirina, Miloslav},
     title = {A simplified proof of the {Sevastyanov} theorem on branching processes},
     journal = {Annales de l'I.H.P. Probabilit\'es et statistiques},
     pages = {1--7},
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     number = {1},
     year = {1970},
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     language = {en},
     url = {http://www.numdam.org/item/AIHPB_1970__6_1_1_0/}
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Jiřina, Miloslav. A simplified proof of the Sevastyanov theorem on branching processes. Annales de l'I.H.P. Probabilités et statistiques, Tome 6 (1970) no. 1, pp. 1-7. http://www.numdam.org/item/AIHPB_1970__6_1_1_0/

[1] B.A. Sevastyanov, Theory of branching processes, (Russian) Uspekhi mat. nauk., 6 (6), 1951, 47-99. | MR 46624 | Zbl 0044.33801