Discussion on the paper by Allin and Hand ανά Smith, PA, Self, A, Michaelson, J, Spence, A, Haskel, J, Murtagh, F, Nason, G, Caan, W, Goldstein, H, King, T, Cocchi, D, Dorling, D, Summa, MG, Le Roux, B, Hall, JF, Herzberg, AM, Liu, H, Longford, NT, Mateu, J, Rondinella, T, Cocchi, D, Ruggeri, K, Stehlik, M, Strelec, L, Vanderweele, TJ, Yu, K, Tian, M, Zini, A, Lara, L, Porcu, E