The phrase "are from a single" is correct and usable in written English.
It can be used when referring to items, people, or elements that originate from one source or category.
Example: "The results of the survey indicate that the majority of respondents are from a single demographic group."
Alternatives: "come from one" or "originate from a single".
Most of the reports of reconstruction after scapulectomy are from a single institution.
However, these results are from a single institution; they are not generalizable.
Points are from a single model run, in which the colour class was changed according to chromatophore age.
All of the dead were in the Honda; the police said all the victims are from a single Bronx family.
Caution should be exercised in interpretation because these results are from a single model with a number of simplifying assumptions.
Test results mentioned in this text are from a single process run, no design iterations were made.
Eight of the Taliban's cabinet-level officials are from a single such madrassa, Haqqania, a "sprawling collection of buildings on the main Islamabad-Peshawar highway".
Almost all the studies purporting to show that antiperspirants cause cancer are from a single laboratory, with Dr Philippa Darbre often the only named author.
Most of the important recent gifts are from a single donor and are gathered in the exhibition "The Art of the Timekeeper: Masterpieces From the Winthrop Edey Bequest," through Feb. 24.
Although the Trump campaign tried to distribute an official slate to avoid wasted votes, there is still significant potential for Trump supporters to cluster their votes as nine of the first 22 Trump delegates are from a single county.
Isolates of the Vibrio cholerae O1 serotype Ogawa from Yemen are from a single sublineage of the seventh pandemic El Tor (7PET) lineage and are susceptible to several commonly used antibiotics as well as to polymyxins.
