"may only apply" is correct and can be used in written English.
It is used to introduce a limitation on something. Example: The discount may only apply to purchases over $100.
Such laws may only apply to relatively small planets relatively close to their suns.
The Bedford Audubon Society, for example, pointed out in a recent fact sheet that cell towers can pose a hazard to migrating birds -- although this may only apply to towers that are lighted at night.
This attempt at justice reform may only apply to federal inmates, in what is a heavily decentralised justice system, but, as Fathi says, it will "redouble pressure" on states to follow suit.
Vikram Amar, a law professor at UC Davis, who has previously suggested that Walker's injunction may only apply to the two couples who sued, conceded that argument had been defeated.
Seasonal sales can only be held during specified weeks, and may only apply to certain products (the list varies depending on whether the sale is in summer or winter).
While a court challenge to the legality of the commission's approval for the Northeast Upgrade is still pending, the outcome may only apply to future pipelines once construction of the new segment gets going, said Maya K. van Rossum, who heads the environmental group.
The findings may only apply to individuals who are similar to those included in this research.
It seems that this may not only apply to humans, but could indeed be the case for many species, amongst which horses.
We hypothesise that this may not only apply to indications for medical intervention but also for guideline adherence and quality of care.
Our new hypothesis may not only apply to the other species known for providing communal care to their offspring which represents 15% of all mammalian species in more than 7 orders (Eisenberg 1981).
This study suggests that the same evolutionary pattern may not only apply to morphological characters, but also to transcriptomic divergence at the level of recently evolved lineages of fish.
