This would usually refer to Lurie’s book.
http://ncatlab.org/nlab/show/Higher+Topos+Theory
http://nlab.mathforge.org/nlab/show/models+for+infinity-stack+(infinity,1)-toposes
Toen: Segal topoi and stacks over Segal categories. File Toen web prepr msri.pdf. Analogous and in some sense equivalent to the notion of model topos, but some advantages. Includes a Giraud type statement characterizing Segal topoi among Segal cats. Notion of homotopy type of a Segal site, improving on the etale homotopy theory of schemes, and more generally on the theory of homotopy types of sites as defined by Artin and Mazur.
nLab page on Higher topos