Dowson, H.R.
Spectral theory of linear operators
Academic Press, 1978
 Buku Teks
Villiers, Johan de
Mathematics of approximation
[Atlantis Press, ], 2012
 eBooks
Singer, Ivan
Best approximation in normed linear spaces by elements of linear subpaces
Springer-Verlag , 1970
 Buku Teks
Neamtu, Marian
Approximation theory XIII: san antonio 2010
[Springer, ], 2012
 eBooks
Bustamante, Jorge
Algebraic approximation: a guide to past and current solutions
[, Springer], 2012
 eBooks