High-resolution X-ray spectra in arbitrary flux units of SSS that contain emission lines without absorption features (SSe, left column) and those that consist of continuum and absorption lines (SSa, right column). Inclination angles i from the literature (if known) are given (see Table 1). The blue thin lines are absorbed blackbody curves, indicating the presence of photospheric emission in all cases. The labels SSS, CN, and RN denote persistent supersoft sources, Classical Novae, and Recurrent Novae, respectively. An apparent emission feature around 40 Å in some Chandra spectra is an instrumental artefact owing to division by low effective areas. All six Chandra spectra of RX J0513.9-6951 (second panel in right column) are co-added, and for V723 Cas (third panel in right column), the two XMM-Newton spectra have been combined with rgscombine.