As you will see from the references on the Wiki page the choice is between
1. "British, Soviet, French and Dutch Battleships" by Gazarke and Dulin published way back in 1980 and
2. "French Battleships 1922-1956" by John Jordan and Robert Dumas published in 2009.
The latter, according to its preface, was based on Dumas' own original research published in French during the early 1990s. So there was at least another 10 years of research behind it, and possibly as much as 29. I have both in my library.
Details of the Alsace class in the former are sketchy being covered by a statement that "It seems reasonable to expect" that the armour and secondary armament would be "similar" to Richelieu and / or Gascoyne and the speed would be "at least" 30knots. They then provide an estimated table of particulars, which isn't too different from the latter book in some respects but significantly different in others. The authors go on to state that no design was selected.
Gazarke & Dulin placed their belief in the 3 quad ship on the basis that the French had "never built a triple turret mounting guns of such large calibre" and therefore it would be "logical" to again choose a quad they were already building.
The latter work has much greater detail about the 3 designs including, armament, armour thicknesses and how they related to that of Richelieu, shp for each type (which varied from 170,000shp to 220,000 shp to produce planned speeds of 31-32 knots). It also spends much more time explaining the development of the aviation arrangements proposed for Gasgoyne and later ships (much more than one catapult and one floatplane). It concludes with the statements -
"The choice of the Naval General Staff was relatively straightforward." It then explains the elimination of the 406mm ship and the 45,000 ton ship for the reasons I previously gave. It then goes on:-
".....Type No. 1, on the other hand, was a well balanced design which used existing weaponry and which could be accomodated with relatively minor adjuatments to current infrastructure.
Two battleships of 40,000 tons were duly authorised on 1 April 1940........."
It then goes on to assign yards and building timetables for the first two ships.
So it seems to me that, without having access to original documents, there is sufficient extra detail about the Alsace class in the latter work to supercede what had been published 29 years earlier in the former work.
