@article {1991, title = {On systems of ordinary differential equations with measures as controls}, journal = {Differential Integral Equations 4 (1991), no.4, p.739-765.}, number = {SISSA;82/89/M}, year = {1991}, publisher = {SISSA Library}, url = {http://hdl.handle.net/1963/840}, author = {Gianni Dal Maso and Franco Rampazzo} }