::::Actually, it is well sourced.  Gil-White is directly sourced, and he directly sources a critique which directly sources a 1969 paper by Jensen.  There isn't any circular reference at all, just a dispute over whether or not two published individuals (Gil-White and Shonemann), have accurately portrayed Jensen's statements in his 1969 paper.  (See Shonemann, P. H. 2005. "Psychometrics of intelligence," in Encyclopedia of social measurement, vol. 3, pp. 193-201: Elsevier. (p.199))