Electronics Letters
Electronics Letters > 1990 > 26 > 2 > 107 - 109
Electronics Letters > 1990 > 26 > 12 > 810 - 812
Electronics Letters > 1990 > 26 > 12 > 816 - 817
Electronics Letters > 1991 > 27 > 20 > 1823 - 1824
Electronics Letters > 1992 > 28 > 18 > 1687 - 1689