Callard, G.V. & Mak, P. & Dubois, W. & Cuevas, M.E. (1989)
Regulation of Spermatogenesis: The Shark Testis Model. Journal of Experimental Zoology, Supplement, 2, 23–34

Callard, G.V. & Mak, P. (1988)
Characteristics and stage-dependent distribution of a novel steroid binding protein in the testis of Squalus acanthias. Steroids, 52(4), 359–360
DOI: 10.1016/0039-128X(88)90146-8

Mak, P. & Callard, G.V. (1987)
A novel steroid-binding protein in the testis of the dogfish Squalus acanthias. General and Comparative Endocrinology, 68(1), 104–112
DOI: 10.1016/0016-6480(87)90065-7

Ruh, M.F. & Singh, R.K. & Mak, P. & Callard, G.V. (1986)
Tissue and species specificity of unmasked nuclear acceptor sites for the estrogen receptor of Squalus testes. Endocrinology, 118(2), 811–818
DOI: 10.1210/endo-118-2-811

Callard, G.V. & Pudney, J.A. & Mak, P. & Canick, J.A. (1985)
Stage-dependent changes in steroidogenic enzymes and estrogen receptors during spermatogenesis in the testis of the dogfish, Squalus acanthias. Endocrinology, 117(4), 1328–1335
DOI: 10.1210/endo-117-4-1328

Callard, G.V. & Mak, P. (1985)
Exclusive nuclear location of estrogen receptors in Squalus testis. Proceedings of the National Academy of Sciences of the United States of America, 82(5), 1336–1340