It would also help if you told us where in the world you are, your options - and the online stores that will sell the kind of high-quality media you need - will be dependent on where you live.
Generally speaking for +R archival, I recommend two types of media.
[li]Taiyo Yuden 8x DVD+R, MID of that will be YUDEN000 T02[/li][li]Verbatim 16x DVD+R, MID code of that will be MCC 004. Seek out Made In Taiwan as a first option, though Made In India is also acceptable for the purpose. Avoid Made In China if you can.[/li][*]If you don’t absolutely need +R, and are holding data that is particularly important, Verbatim Archival Grade DVD-R 8x has a scratchguard layer and a gold layer protecting the reflective later and high quality AZO dye. That will be marketed as “Verbatim Archival Grade” and the MID will be MCC 02RG20[/ol]Taiyo Yuden is my favourite DVD maker (followed closely by Verbatim) and good quality media of the 3 kinds mentioned above are (as far as I know) available mostly online in both Europe and North America.