[jebus989]

These are indeed links but quite random ones. Mostly they are reporting that growing two things together in a field can give higher yields than growing a single thing. None seem to be related to GMOs, which could obviously also be grown with complimentary species to increase yield.

[animal_spirits]

Correct, these are papers on monocultures vs non monocultures. But GMOs are inclined to be grown in monocultures.

[jebus989]

All crops are inclined to be grown in monocultures. That's because even if you'd get more yield pairing with other species — as in these studies — pragmatically the time and cost of sowing, harvesting and separating multiple species outweighs the theoretical yield gain per unit area of a monocrop.