XML (Document markup language).

ADO.NET and XML : ASP.NET on the edge by: Beamer, Gregory A. (Language materials, printed)

XML bible by: Harold, Elliotte Rusty (Language materials, printed)

XML your visual blueprint for building expert web pages by: Vander Veer, Emily A.; Mengle, Rev (Language materials, printed)

XML : how to program by: Deitel, H. M. ... [et al.] (Language materials, printed)