Ruiz-Cooley, R. I, D. T. Engelhaupt & J. G. Ortega-Ortiz. 2011. Contrasting C and N isotope ratios from sperm whale skin between the Gulf of Mexico and Gulf of California: effect of habitat. Marine Biology. DOI 10.1007/s00227-011-1795-3.
Ruiz-Cooley, R. I., K. Y. Garcia & E. D. Hetherington. 2011. Effects of lipid removal and preservatives on carbon and nitrogen stable isotope ratios of squid tissues: Implications for ecological studies. Journal of Experimental Marine Biology and Ecology. 407: 101–107.
Staaf, D. J., R. I. Ruiz-Cooley, C. Elliger, Z. Lebaric, B. Campos, U. Markaida & W. F. Gilly. 2010. Ommastrephid squids in the Central and Eastern Pacific show a convergent biogeographic break but divergent population structures. Marine Ecology Progress Series. 418: 165-178.
Ruiz-Cooley R. I. & D. T. Engelhaupt. 2010. Trophic Aspects of Sperm Whales (Physeter macrocephalus) in the Northern Gulf of Mexico Using Stable Isotopes of Carbon and Nitrogen Report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA, OCS Study MMS 2008-000, 21 pp.
Ruiz-Cooley, R. I., E. C. Villa & W. R. Gould. 2010. Ontogenetic variation of δ13C and δ15N recorded in the gladius of the jumbo squid Dosidicus gigas: geographic differences. Marine Ecology Progress Series. 399: 187-198.
Ruiz-Cooley, R. I. 2009. Insights into the trophic ecology of sperm whales (Physeter macrocephalus) and jumbo squid (Dosidicus gigas): geographic variation in stable isotopes. PhD dissertation, New Mexico State University, Las Cruces, USA.
Ruiz-Cooley, R. I. & U. Markaida. 2007. Use of stable isotopes to examine the foraging ecology of jumbo squid Dosidicus gigas. The Role of Squid in Pelagic Marine Ecosystem, GLOBEC Report 24: 62-63 Honolulu, Hawaii, USA.
Ruiz-Cooley, R. I., U. Markaida, D. Gendron & S. Aguiñiga. 2006. Stable isotopes in jumbo squid (Dosidicus gigas) beaks to estimate its trophic position: comparison between stomach content and stable isotopes. Journal of the Marine Biological Association of the United Kingdom. 86: 437-445.
Ruiz-Cooley, R. I., D. Gendron, S. Aguiñiga & S. Mesnik. 2004. Trophic relationship between sperm whales and jumbo squid using stable isotopes of C and N. Marine Ecology Progress Series. 277:275-283.