[1] Ewa ŁAZAROW: On the Baire class of I-approximate derivatives. (to appear).
[2] W. POREDA E. WAGNER-BOJAKOWSKA W. WILCZYŃSKI:
A category analogue of the density topology. Fund. Math. (1985).
MR 0813753
[3] W. POREDA E. WAGNER-BOJAKOWSKA W. WILCZYIŃSKI:
Remarks on I-density and I-approximately continuous functions. Comment. Math. Univ. Carolinae 26 (1985), 553-563.
MR 0817826