Roberts, J. W., & Huelbig, C. (1996). City kids & city critters!: Activities for urban explorers from the Houston Arboretum & Nature Center. Learning Triangle Press.
Lua i Stíl Chicago (17ú heag.)Roberts, Janet Wier, agus Carole Huelbig. City Kids & City Critters!: Activities for Urban Explorers from the Houston Arboretum & Nature Center. New York, NY: Learning Triangle Press, 1996.
Lua MLA (8ú heag.)Roberts, Janet Wier, agus Carole Huelbig. City Kids & City Critters!: Activities for Urban Explorers from the Houston Arboretum & Nature Center. Learning Triangle Press, 1996.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.