Resolution: standard / high
/ Figure 1. ... Haematoxylin and eosin stained bilaminar yolk sac (BYS, A.) and trilaminar yolk sac (TYS, B.) showing trophoblast cells (Tr), yolk sac endodermal cells (En), and, in the trilaminar yolk sac only,...
http://www.biomedcentral.com/1471-2148/8/163/figure/F1