Recently Type II codes over ℤ4 have been introduced as self-dual codes containing the all-one vector with the property that all Euclidean weights are divisible by eight. The notion of extremality for the Euclidean weight has been also given. In this paper, we give two methods for constructing Type II codes over ℤ4. By these methods, new extremal Type II codes of lengths 16, 24, 32 and 40 are constructed from weighing matrices.
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