1. Evans, M.J., Humke, P.D.: Generalizations of Young’s Theorem to real functions of several variables, Rend. Circ. Mat. Palermo, Ser. II, 58 (2009), 287–296
2. Kellum, K.R.: Functions that separate X × % MathType!MTEF!2!1!+- % feaagaart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBqj3BWbIqubWexLMBb50ujbqegm0B % 1jxALjharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqr % Ffpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0F % irpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaa % GcbaWefv3ySLgzgjxyRrxDYbqehuuDJXwAKbIrYf2A0vNCaGqbaiab % -Xrisbaa!453D! $$ \Re $$ , Houston J. Math. (to appear)
3. Young, W.H.: A theorem in the theory of functions of a real variable, Rend. Circ. Mat. Palermo, Ser. I, 24 (1907), 187–192