That was me who's been bothering you about that article for some time.
Although I got the Guns & Ammo magazine, where this is from, couple months ago, thanks for posting it anyway.
IMO, there's a better article titled "Swivel Guns of Southeast Asia" or something, in some old Gun Digest magazine.
The GD one is much longer with more info on types, sizes, origins etc and has many many more photos in it.
I have also a small "booklet" titled "Brunei Cannon" which is also very good one, but not really for general info on lantakas since it concentrates only on Brunei made ones. There's also a book called "The Keris and other Malay Weapons" which has a part on lantakas (possibly other malay cannons too) but I haven't got that (yet) so I can't say if it's any good.