Wild potato collecting expedition in Southern Peru (Departments of Apurímac, Arequipa, Cusco, Moquegua Puno, Tacna in 1998: Taxonomy and new genetic resources
Comparison of “Remote” Versus “Easy” In Situ Collection Locations for USA Wild Solanum (potato) Germplasm
A Morphometric Study of Species Boundaries of the Wild Potato Solanum Series Piurana (Solanaceae) and Putatively Related Species from Seven Other Series in Solanum Sect. Petota (2008)
A Morphometric Study of Species Boundaries of the Wild Potato Solanum Series Conicibaccata: a Replicated Field Trial in Andean Peru (2008)
Taxonomy of Mexican and Central American Members of Solanum Series Conicibaccata (sect. Petota) (2001)