Could possibly be of interest to you....Price comparison results and super-replication: an application to passport optionsHenderson, V., Applied Stochastic Models in Business and Industry, 2000, vol. 16, no. 4, pp. 297-310 Riskless Trading: Passport Options, Fund Managers and the Prudent Investor Rule.Company and Securities Law Journal, 2000, vol. 18, no. 3, pp. 209 also several download papers on passport options athttp://
www.math.ethz.ch/~vh/preprints.html