There you go, wst - simple!
This from a 2009 PPRune post - bear in mind the FCOM reference may be out-of-date
"According to Airbus F-COM 3.04.10
VS or Stalling speed, it is not displayed. Moreover, for a conventional A/c, the reference stall speed, VSmin is based on a load factor that is less than 1g. This gives a stall speed that is lower than than the stall speed at 1g.
All operating speeds are expressed as functions of this speed (for instance VREF = 1.3 VSmin). Because A/c of the A320 family have a low speed protection featute (alpha limit) that the flight crew can not override, the airworthiness authorities have reconsidered the definition of stall speed for these A/c.
All operating speeds must be referenced to a speed that can be demonstrated by flight test. The speed is designated as VS1g. Airworthiness authorities have agreed that a factor of .94 represents the relationship between VS1g for A/c of the A320 family and VSmin for conventional A/c types. As a result tha authorities allow A/c of the A320 family to use the following factors:
V2 = 1.2 * .94 VS1g = 1.13 VS1g
VREF = 1.3 * .94 VS1g = 1.23 VS1g
FCOM concludes by saying that the A319,320,321 hav exactly the same maneuver margin that a conventional A/c would have at its reference speeds."