Vitamin B6 intake, its active form pyridoxal 5'phosphate, and markers of B6 activity and catabolism - Clasen, J; Heath, AK; Van, Puyvelde H; Huybrechts, I; Johansson, M; Ferrari, P; Park, JY; Brennan, P; Riboli, E; Muller, DC (Oxford University Press, 2021)