The phrase "are found in certain" is correct and usable in written English.
It can be used when discussing the presence or occurrence of something within specific categories or groups.
Example: "These species are found in certain regions of the Amazon rainforest, where the climate is ideal for their growth."
Alternatives: "are located in specific" or "can be seen in particular".
"You can imagine certain microbes are found in certain places," Ms. Dutton said.
Trout and bass are found in certain streams throughout the state.
Uric acid is a waste product produced by the body when it breaks down chemicals called purines, which are found in certain foods.
Walker began his work at Cambridge by studying the proteins encoded by DNA that are found in certain bacteriophages and in mitochondria, the energy-producing organelles of animal cells.
Trace quantities of germanium are found in certain zinc blendes, in sulfidic ores of copper and arsenic, and in coals, the latter possibly a consequence of the concentration of the element by plants of the Carboniferous Period in geologic history.
Although it is doubtful that there is any direct Jewish source of gnosticism, some characteristic gnostic doctrines are found in certain groups of particularly apocalyptic 1st-century Jews the dichotomy of body and soul and a disdain for the material world, a notion of esoteric knowledge, and an intense interest in angels and in problems of creation.
Augites may be found in certain metamorphic rocks, notably marbles.
Social parasitism, another fascinating aspect of post-fertilization behaviour, is found in certain insects and birds.
In 1964 they announced that prostaglandins are derived from arachidonic acid, an unsaturated fatty acid that is found in certain meats and vegetable oils.
Chlorophylls a and b are the chief forms in higher plants and green algae; bacteriochlorophyll is found in certain photosynthetic bacteria.
This molecule is found in certain cells of the immune system, which is why that is the part of the body affected by HIV.
