ドナルド・スペンサー
(1959), Advanced Calculus, Princeton, N.J.: Van Nostrand Dover reprint. (2011). ISBN 978-0-4864-8090-9; pbk
Kumpera, A.; Spencer, D. C. (1972), Lie Equations: Volume I, General Theory, AM-73, Annals of Mathematical Studies, Princeton University Press, ISBN 978-0-6910-8111-3; pbk
Kumpera, A.; Spencer, D. C. (1974), Systems of Linear Partial Differential Equations and Deformation of Pseudogroup Structures, Les Presses de l'Université de Montréal