http://www.akhbaroka.co.vu/2014/01/blog-post_8491.html?sc=1653283647734#c27523971826501624
https://sites.lafayette.edu/berkins/2013/02/22/the-caravel-and-the-impact-of-new-technologies-on-transportation-systems/comment-page-223/#comment-935113
https://sites.lafayette.edu/berkins/2013/03/09/budget-airlines-how-do-they-do-it/comment-page-41/#comment-935146
https://sites.lafayette.edu/berkins/2013/02/24/eulogy-for-a-fallen-giant-2/comment-page-11/#comment-935143
https://sites.lafayette.edu/berkins/2013/03/15/should-transportation-systems-be-public-or-private/comment-page-23/#comment-935152