This article presents a survey of the developments of univariate GARCH models. ARCH, GARCH, EGARCH and other possible nonlinear extensions are examined. Conditions for stationarity (weak and strong) are presented. Inference and testing is presented in the quasi-maximum likelihood framework....

The paper was originally written in Danish as part of a planned book which found no publisher. Readers of the present abstract who cannot read Danish may find some quotations given in English in the Danish text, so it may be useful to give references to page numbers in that text in the present...