I find some more words in my FCOM PERFORMANCE Chapter, as below:
REFERENCE SPEED (VREF)
VREF is equal to the VLS of CONF FULL. VREF is used to determine the Final Approach Speed (VAPP) when a system failure affects the landing performance.
GO-AROUND SPEED
In the case of a missed approach, the go-around climb gradient is calculated at the go-around speed.
The standard go-around speed is 1.23 VS1G of the go-around configuration. For approaches with a decision height at or above 200 ft, where approach climb performance is found restrictive, the go-around speed can be increase up to 1.3 VS1G of the go-around configuration.