@article{10_1017_S0017089500001117,
     author = {Haruki, Hiroshi},
     title = {On a functional equation for the exponential function of a complex variable},
     journal = {Glasgow mathematical journal},
     pages = {31--34},
     year = {1971},
     volume = {12},
     number = {1},
     doi = {10.1017/S0017089500001117},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500001117/}
}