Composition	Volume	Final concentration
IF9S (see recipe)	25 ml
Activin A (25 µg ml−1; see recipe)	15 µl	15 ng ml−1
BMP4 (25 µg ml−1; see recipe)	40 µl	40 ng ml−1
CHIR (4 mM; see recipe)	9.4 µl	1.5 µM