Vref_cal on STM32F3xx ADC
One simple way is the following:

#define VREFINT_CAL_ADDR    0x1FFFF7BA

uint16_t vrefint_cal;                        // VREFINT calibration value
vrefint_cal= *((uint16_t*)VREFINT_CAL_ADDR); // read VREFINT_CAL_ADDR memory location


Or a more general is to simply create a pointer and assign 0x1FFFF7BA to it, and then the rest is the same.