A remark on endomorphisms of abelian varieties over function fields of finite characteristic
Yu. G. Zarhin

References
1.	Zarkhin Yu. G., “Teorema konechnosti dlya izogenii abelevykh mnogoobrazii nad funktsionalnymi polyami konechnoi kharakteristiki”, Funktsionalnyi analiz i ego prilozheniya, 8:4 (1974), 31–34
2.	Tate J., “Algebraic cycles and poles of Zeta-functions”, Arithmetical algebraic geometry, New York, 1965, 93–110
3.	Tate J., “Endomorphisms of abelian varieties over finite fields”, Inv. Math., 2 (1966), 134–144        ; Matematika, 12:6 (1968), 31–46
4.	Parshin A. N., “Minimalnye modeli krivykh roda 2 i gomomorfizmy abelevykh mnogoobrazii, opredelennykh nad polem konechnoi kharakteristiki”, Izv. AN SSSR. Ser. matem., 36 (1972), 67–109