We study a generalization of the classical Henstock-Kurzweil integral, known as the strong -integral, introduced by Jarník and Kurzweil. Let  be the space of all strongly -integrable functions on a multidimensional compact interval , equipped with the Alexiewicz norm . We show that each element in the dual space of  can be represented as a strong -integral. Consequently, we prove that  is strongly -integrable on  for each strongly -integrable function  if and only if  is almost everywhere...