Jantsch, J. (2010). Referral engine: Teaching your business to market itself. Portofolio.
Lua i Stíl Chicago (17ú heag.)Jantsch, John. Referral Engine: Teaching Your Business to Market Itself. London: Portofolio, 2010.
Lua MLA (9ú heag.)Jantsch, John. Referral Engine: Teaching Your Business to Market Itself. Portofolio, 2010.
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