@article{AM2_1985__28_137051,
     author = {Hiroshi Haruki},
     title = {A proof of {Euler's} identity by a functional equation.},
     journal = {Aequationes mathematicae},
     pages = {138--143},
     publisher = {mathdoc},
     volume = {28},
     year = {1985},
     zbl = {0561.30019},
     url = {http://geodesic.mathdoc.fr/item/AM2_1985__28_137051/}
}