Roberts, J. W., & Huelbig, C. (1996). City kids & city critters!: Activities for urban explorers from the Houston Arboretum & Nature Center. Learning Triangle Press.

Roberts, Janet Wier, and Carole Huelbig. City Kids & City Critters!: Activities for Urban Explorers from the Houston Arboretum & Nature Center. New York, NY: Learning Triangle Press, 1996.

Roberts, Janet Wier, and Carole Huelbig. City Kids & City Critters!: Activities for Urban Explorers from the Houston Arboretum & Nature Center. Learning Triangle Press, 1996.