Gokmen Ozel H, Kucukkasap T, Koksal G, Kalkanoglu Sivri HS, Dursun A, Tokatli A, Coskun T. Does maternal knowledge impact blood phenylalanine concentration in Turkish children with phenylketonuria? J of Inher Metab Disea. 2008 Jun 27;31(S2):213–7. doi: 10.1007/s10545-008-0775-3.