Heyd, T. (1999). Rock art aesthetics: Trace on rock, mark of spirit, window on land. [s.n.].
Chicago Style (17th ed.) CitationHeyd, Thomas. Rock Art Aesthetics: Trace on Rock, Mark of Spirit, Window on Land. [S.l.]: [s.n.], 1999.
MLA (9th ed.) CitationHeyd, Thomas. Rock Art Aesthetics: Trace on Rock, Mark of Spirit, Window on Land. [s.n.], 1999.
Warning: These citations may not always be 100% accurate.