Gwinner, E., & Schwabl-Benzinger, I. (1982). Adaptive temporal programming of molt and migratory disposition in two closely related long-distance migrants, the pied flycatcher (Ficedula hypoleuca) and the collared flycatcher (Ficedula albicollis). In F. Papi, & H. G. Wallraff (Eds.), Avian Navigation (pp. 75-89). Berlin, Heidelberg: Springer.