list of TTP projects with exact code:
https://github.com/markuswagnergithub/seal2017ExactApproachesForTheTravellingThiefProblem from SEAL 2017: exact approaches, single-objective
https://github.com/markuswagnergithub/gecco2018Evolutionary-ComputationplusDynamicProgrammingfortheBi-ObjectiveTravellingThiefProblem from GECCO 2018: exact approaches are used inside a multi-objective approach