Haggstram, F. M., and E. W. Zettler. “Complex Sleep Apnea: Worsening of Symptoms With CPAP Use for Obstructive Sleep Apnea <b>[Abstract in English]</I>”. Scientia Medica, vol. 20, no. 2, Sept. 2010, pp. 172-5, https://revistaseletronicas.pucrs.br/ojs/index.php/scientiamedica/article/view/3742.