Deux articles qui traitent l’identification de Gobemouche de l’Atlas (Ficedula speculigera) et les espèces similaires: Gobemouche noir européen (F.h. hypoleuca) et ibérique (F.h. iberiae), Gobemouche à collier (F. albicollis) et les hybrides albicollis x hypoleuca
Two articles dealing with field identification of the Atlas Pied Flycatcher (Ficedula speculigera) and similar species.
The first article is about the variability of plumage and morphology of the Atlas Pied Flycatcher and the overlapping characters with the Iberian Pied Flycatcher (Ficedula h. iberiae) and other similar species: European Pied Flycatcher (Ficedula h. hypoleuca), Collared Flycatcher (Ficedula albicollis) and also hybrids albicollis x hypoleuca.
Corso, A., Janni, O., Viganò, M. & Starnini, L. (2015). Atlas Pied Flycatcher: variability of identification characters. Dutch Birding 37: 141–160.
PDF in ResearchGate.net
A second article about the call identification:
Robb, M. & The Sound Approach (2015). Call identification of European Pied, Iberian Pied and Atlas Pied Flycatcher. Dutch Birding 37: 161–163.

breeding grounds in Morocco and Tunisia in May. From figure 1 of Corso et al. Dutch Birding 37: 141–160.