Automatica. A Journal of IFAC, the International Federation of Automatic Control (Automatica J. IFAC) (19920101), 28, no.~6, 1229-1233. ISSN: 0005-1098 (print).eISSN: 1873-2836.
Automatica. A Journal of IFAC, the International Federation of Automatic Control (Automatica J. IFAC) (19890101), 25, no.~4, 593-596. ISSN: 0005-1098 (print).eISSN: 1873-2836.