The phrase "are exclusively of" is correct and usable in written English.
It can be used to indicate that something is solely composed of or limited to certain elements or characteristics.
Example: "The ingredients in this recipe are exclusively of organic origin, ensuring the highest quality."
Alternatives: "are solely composed of" or "are only made up of".
In the centre of the macula is a depression, called the fovea, which contains specialized nerve cells that are exclusively of the type known as cones.
That's not to say that American Hindus are exclusively of Indian and Indo-Caribbean descent.
The ideas I have during my long weekend rides, typically of two to five hours, are exclusively of the exposition/writing/planning talks/grant proposals kind, including actual sentences I will use.
Serum concentrations of plant sterols that are exclusively of dietary origin, such as sitosterol and campesterol, reflect the efficacy of cholesterol absorption [3], [6].
One of the specific features of STOX1, as depicted in the primary study, was its allele-specific expression from maternal alleles, since the authors showed that STOX1 mRNA was absent in hydatiform moles, which are exclusively of paternal origin [1].
Such overrepresented transcripts are exclusively of hypothetical function or are involved in the stress response.
"In the 1970's, when we joined, the choice of officers was exclusively of a high order," Golubev said.
Most of the canonical literature is exclusively of religious interest, but interspersed in it are works of considerable literary interest.
All first-degree familial MA cases (N = 3/56) were exclusively of maternal origin.
In three cases these were exclusively of 'compact' morphology with no demonstrable 'skeins' (Figures 2d,g,h, i).
HMPV strains from Bangkok were exclusively of genotype A, though previously determined strains of Japanese origin grouped in genotype B (clades 2 and 3).
