Eichele, G. 1989. Retinoic acid induces a pattern of digits in anterior half wing buds that lack the zone of polarizing activity. Gilbert, S.E. 1994. Sinauer Associates, Inc., Sunderland, Massachusetts. Noji, S. et.
Retinoic acid induces polarizing activity but is unlikely to be a morphogen in the chick limb bud.
Rossant, J., Zirngibl, R., Cado, D., Shago, M. and Giguere, V., 1991. Expression of a retinoic acid response element-hsplacZ transgene defines specific domains of transcriptional activity during mouse embryogenesis. Summerbell, D. 1979. Wanek, N., Gardiner, D.M., Mueoka, K. and Bryant, S.V., 1991. Conversion by retinoic acid of anterior cells into ZPA cells in the chick wing bud.