Zeng, Guojun. Evolution of muddle-class Chinese outbound travel preferences: an international perspective / Guojun Zeng, Frank Go. - 2013. // Tourism economics : the business and finance of tourism and recreation. Vol. 19 (2013), No. 2
Ammann, Paul A.. Segmentation of the Swiss travel market by holiday activities / Paul A. Ammann, Lukas Bischof, Felix Schalcher. - 2002. // Tourism review = Revue de tourisme = Zeitschrift für Fremdenverkehr. Vol. 57 (2002), No. 4