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We present two direct product-type constructions which will prove useful in the construction of resolvable designs. We use our constructions to complete the spectrum for resolvable groupdivisible designs with block size three, as well as to give a short proof of the existence of decompositions of &,, into a one-factors and b triangle-factors for any a, b, n with a + 2b = 6n -1 and a > 1. 0 1 9 9 3 John Wiley & Sons, Inc.

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We investigate the spectrum for {4}-GDDs of type g u m 1. We determine, for each admissible pair (g, u) (with some exceptions), the maximum and minimum values of m for which a {4}-GDD of type g u m 1 exists.

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