Another reference mismatch here:
This dorso-ventral polarity is also present in the hands, with an obvious palmar and a dorsal side. Bio-chemically, this difference seems to be related to the genetic pathway of en1 and wnt-7a , and analogous genes may be at play in the dorso-ventral polarity of insect wings . But the expression of specific genetic pathways is related actually to the geometry of the limb bud at the moment of formation: if the limb bud forms from endoderm and ectoderm, it has dorso-ventral polarity (like a normal hand), if a limb bud forms more proximally by a fold of ectoderm only, the limb paddle has double dorsal polarity1 .
where ref 62 is
given as E. McGlinn, C.J. Tabin, Curr. Opin. Gen. Devel. 16, 426 (2006), corresponding to: Edwina McGlinn, Clifford J. Tabin, Mechanistic insight into how Shh patterns the vertebrate limb, Current Opinion in Genetics & Development, Volume 16, Issue 4, Pattern formation and developmental mechanisms, August 2006, Pages 426-432, ISSN 0959-437X, DOI: 10.1016/j.gde.2006.06.013.
Which have no mention of en1 and wnt-7a, and doesn’t discuss dorso-venrtal patterning and double dorsal polarity; but it’s written by people understanding limb patterning and AER formation, a nice reading, so you will enjoy it if you are interested by the subject.
But not if you are just seeking information about how Fleury formed his point of view.
On the other forelimb, there is a lot of papers dealing with the dorsoventral patterning of limbs.
We have here a second instance of Fleury’s point of view on how the AER is formed 😀 ROFL etc.