; Library of Congress, National Library Service for the Blind and Physically Handicapped«Say How?» (en anglès). loc.gov/nls/. [Consulta: 4 maig 2020]..
mentalfloss.com
M. Arbeiter. «15 Things You Might Not Know About "Stranger in a Strange Land"» (en anglès). mentalfloss.com, 14-07-2015. «The apex of Heinlein’s career and a cornerstone of its genre, the sociopolitical allegory is now recognized as a landmark of American literature.»