Constraints listed in the Nation and Crabbe article

P​‌‍‍‍‌‍‍‌‌‍‍‍‌‍‍‍‍‌‍‍​lease look at the constraints listed in the Nation and Crabbe article. What other constraints are ​‌‍‍‍‌‍‍‌‌‍‍‍‌‍‍‍‍‌‍‍​described in other parts of the article? What constraint had the strongest effect on their course​‌‍‍‍‌‍‍‌‌‍‍‍‌‍‍‍‍‌‍‍​?