@article{700190,
     title = {Perron integral, Perron product integral and ordinary differential equations},
     booktitle = {Equadiff 6},
     series = {GDML\_Books},
     publisher = {J. E. Purkyn\v e University, Department of Mathematics},
     address = {Brno},
     year = {1986},
     pages = {[149]-154},
     mrnumber = {MR0877117},
     zbl = {0619.26006},
     url = {http://dml.mathdoc.fr/item/700190}
}

Kurzweil, Jaroslav; Jarník, Jiří. Perron integral, Perron product integral and ordinary differential equations, dans Equadiff 6, GDML_Books,  (1986), pp. [149]-154. http://gdmltest.u-ga.fr/item/700190/