In 1971, Doyen and Vandensavel gave a special doubling construction that gives a direct construction of 2-chromatic SQS (v) for all v ≡ 4 or 8 (mod 12). In this paper, we introduce the concept of a 2-chromatic candelabra quadruple system, and use it to provide a construction for 2-chromatic SQS. It is proved that a 2-chromatic SQS (v) exists if v ≡ 10 or 26 (mod 48), or if v ≡ 2 or 34 (mod 96) with the possible exception v = 98. © 2006 Elsevier Ltd. All rights reserved.
Ji, L. (2007). A construction for 2-chromatic Steiner quadruple systems. European Journal of Combinatorics, 28(6), 1832–1838. https://doi.org/10.1016/j.ejc.2006.04.009