The Plant Ontology Database: a community resource for plant structure and developmental stages controlled vocabulary and annotations. - Shulamit Avraham; Chih-Wei Tung; Katica Ilic; Pankaj Jaiswal; Elizabeth A. Kellogg; Susan McCouch; Anuradha Pujar; Leonore Reiser; Seung Yon Rhee; Martin M. Sachs; Mary L. Schaeffer; Lincoln Stein; et al. (Nucleic Acids Res., 2008)

Computable visually observed phenotype ontological framework for plants. - Jaturon Harnsomburana; Jason M. Green; Adrian S. Barb; Mary L. Schaeffer; Leszek Vincent; Chi-Ren Shyu (BMC Bioinform., 2011)