Upper and lower Henstock integrals
Using the concept of a contractive set-valued function defined on the set of all nondegenerate closed subintervals of \([0,1]\) the upper and lower Riemann-type integral sums are defined and it is shown that using them the Kurzweil-Henstock integral can be defined similarly as in the case of the well-known Riemann integral.
scientific article; zbMATH DE number 1450295