ドナルド・スペンサー
Schaeffer, A. C.; Spencer, D. C. (1950), Coefficient Regions for Schlicht Functions, American Mathematical Society Colloquium Publications, Vol. 35, Providence, R.I.: American Mathematical Society, ISBN 978-0-8218-1035-4, MR0037908, https://books.google.com/books?id=9a_wigDUPloC
Schiffer, M. M.; Spencer, D. C. (1955), Functionals of Finite Riemann Surfaces, Princeton University Press
Nickerson, H. K.; Spencer, D. C.; Steenrod, N. E.