[1] T. Evans: Products of points-some simple algebras and their identities. Amer. Math. Monthly, 74 (1967), 362-372. MR 0209382 | Zbl 0207.32901

[2] M. Saade: On decompositions of groupoids. preliminary report, Notices Amer. Math. Soc, 17 (1970), 91-92.