The phrase "a very valuable source" is correct and usable in written English.
You can use it when referring to a resource or reference that provides significant information or insight.
Example: "The research paper proved to be a very valuable source for my thesis on climate change."
Alternatives: "an extremely useful resource" or "a highly beneficial reference."
New applications like Facebook's Glimpse are potentially a very valuable source of this sort of intelligence.
In several states, for instance, the school-meal menu now includes eggs, a very valuable source of animal protein for growing children.
Workflow logs captured by different cross-organizational systems provide a very valuable source of information on how business processes are executed in reality and thus can be used to derive workflow models through process mining.
Overall, we consider that the TEDS-M international database provides a very valuable source for new findings in the field of mathematics teacher education, offering scope for valid results, but only if the attributes of the datasets are properly considered during analyses.
The grey literature, therefore, is a very valuable source of relevant information.
Darwin's finches continue to be a very valuable source of biological discovery.
However, we have one very valuable source that records the intimate relationship of his study and even spiritual discipleship in a literary-poetic collection of the early 17th century from Qazvin known as the Jung-e Qazvin.
However, depending on it alone to form your opinion can cause you to miss six billion other very valuable sources of insight.
Then here we go.... President Trump gave away secret intelligence to the Russians in the Oval Office, and by doing so might have compromised an very valuable Israeli source within the Islamic State.
Owing to phytochemical constituents synthesized by medicinal plants, the plants are considered a very valuable and rich source to obtain the bioactive molecules.
Forward genetics screening has historically been a very valuable strategy to identify different sources of soybean traits.
