^The Substitution of Aryl Iodides with Cuprous Acetylides. A Synthesis of Tolanes and Heterocyclics R. D. Stephens and C. E. Castro J. Org. Chem.; 1963; 28(12); pp 3313 - 3315; doi:10.1021/jo01047a008
^D. C. Owsley and C. E. Castro.Organic Syntheses, Coll. Vol. 6, p.916 (1988); Vol. 52, p.128 (1972) Link.