Levels of unreality : studies in structure and construction in Italian mural painting during the Renaissance / Sven Sandström. - Stockholm : Almqvist & Wiksell [distributor], 1963. - 260 s. : kuv. ; 27 cm. - (Acta Universitatis Upsaliensis. Figura, Uppsala studies in the history of art. New Series / editor Nils Gösta Sandblad ; 4)