MR0350236
Drobot, V.
Vladimir DROBOT
Discontinuous Solutions of the Functional Equation $f(x+y)=H(f(x),f(y))$
Funkcialaj Ekvacioj. Serio Internacia
16
1973
165--168
http://fe.math.kobe-u.ac.jp/FE/Free/vol16/fe16-3-1.pdf
http://fe.math.kobe-u.ac.jp/FE/FE_pdf_with_bookmark/FE11-20-en_KML/fe16-165-168/fe16-165-168.pdf
http://www.ams.org/mathscinet-getitem?mr=MR0350236
fe16-053-067
1973
Discontinuous Solutions of the Functional Equation $f(x+y)=H(f(x),f(y))$
Drobot, V.
Drobot, V.
5
Aczé1, J.
Lectures on functional equations and their applications
New York
1966
MR0208210
2
Hamel, G.
Eine Basis aller Zahlen und die *nstetigen Lösungen der Funktionalgleichung: $f(x+y)=f(x)+f(y)$
Math. Ann.
60
1905
459-462
MR1511317
3
Hewitt, E.; Zuckerman, H. S.
Remarks on the functional equation $f(x+y)=f(x)+f(y)$
Mathematics Magazine
42
1969
121-123
MR0246007