Only the endophyll-Rauber's sickle complex and not cells derived from the caudal marginal zone induce a primitive streak in the upper layer of avian blastoderms Marc Callebaut, Emmy Van Nueten, Luc Van Nassauw, Hilde Bortier and Fernand HarrissonReprod. Nutr. Dev., 38 4 (1998) 449-463DOI: https://doi.org/10.1051/rnd:19980409