The phrase "are provided by several" is correct and usable in written English.
It can be used when discussing resources, services, or information that come from multiple sources.
Example: "The necessary materials for the project are provided by several suppliers to ensure timely delivery."
Alternatives: "are supplied by various" or "are offered by multiple".
E-services are provided by several web-enabled companies.
The tools used are provided by several generalizations of Bessel inequality due to Boas-Bellman, Bombieri, and the author.
Because various types of motorized stages are provided by several companies, we selected an appropriate type for the system from the viewpoints of position accuracy, size of the system and samples to be analyzed.
Bus services are provided by several operators including First Group, which provides services from the East Riding into York, Goole Town Service and also services from Goole to Doncaster.
Genetic markers are provided by several database resources, which have a web interface to allow the users to browse genetic linkage maps.
Dream spikes following FHB infection are provided by several up-regulated putative 1-aminocyclopropane-1-carboxylate (ACC) oxidases and GDSL-like lipases genes.
However, few RCTs have been performed on CAMs as there is little incentive for manufacturers to undertake the considerable financial investments required for phase 1 4 clinical trials that assess efficacy, effectiveness, safety and cost-effectiveness [ 5] when individual CAMs may be provided by several providers and can not be protected by patent.
One common non-invasive treatment is manual therapy, which is provided by several groups of health care providers such as naprapaths, physiotherapists, chiropractors and osteopaths.
These comments were provided by several personalities.
Medical education is provided by several medical colleges and an institute of postgraduate medicine at Dhaka.
