@article{10_1017_S0017089500003864,
     author = {Armitage, D. H.},
     title = {On the derivatives at the origin of entire harmonic functions},
     journal = {Glasgow mathematical journal},
     pages = {147--154},
     year = {1979},
     volume = {20},
     number = {2},
     doi = {10.1017/S0017089500003864},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500003864/}
}