Friedman, Avner
Variational principles and free-boundary problems
John Wiley & Sons, 1982
 Buku Teks SO
Kinderlehrer, David
An introduction to variational inequalities and their applications
Society for Industrial and Applied Mathematics, 2000
 eBooks
Lanczos, Cornelius
The variational principles of mechanics/ Cornelius Lanczos
University of Toronto Press, 1966
 Buku Teks
Fokas, Athanassios S., 1952-
A unified approach to boundary value problems
Society for Industrial and Applied Mathematics, 2008
 eBooks
Keskin, Ali Ümit
Boundary Value Problems for Engineers : with MATLAB Solutions
Springer Cham, 2019
 eBooks