Gibson, S.A., et al. “Ultrapotassic Magmas Along the Flanks of the Oligo-Miocene Rio Grande Rift, USA: Monitors of the Zone of Lithospheric Mantle Extension and Thinning Beneath a Continental Rift”. International Kimberlite Conference: Extended Abstracts, vol. 5, Feb. 1991, pp. 133-5, doi:10.29173/ikc2489.