Thrifty Guides #3: The Thrifty Guide to Ancient Greece (A Handbook for Time Travelers) (미국판)

Thrifty Guides #1: The Thrifty Guide to Ancient Rome (A Handbook for Time Travelers) (미국판)

Thrifty Guides : The Thrifty Guide to Medieval Times (A Handbook for Time Travelers) (미국판)

Thrifty Guides #2 : The Thrifty Guide to the American Revolution (A Handbook for Time Travelers) (미국판)