"scarcely documented" is correct and usable in written English.
You can use it to indicate that something only has limited or unreliable documentation to support it. For example: "The effects of this new drug on elderly patients has been scarcely documented."
Roughly two months into this important yet scarcely documented battle, Syria's antigovernment fighters have succeeded in laying siege to the heavily fortified Abu ad Duhur air base.
Life Cycle Assessment (LCA) is scarcely documented for stormwater systems despite their ubiquitous implementation.
Effective gene flow between GM rice and wild species is scarcely documented, possibly owing to the fact that GM rice is not yet commercially cultivated worldwide.
Concrete dams with expansions from different origins are rare and scarcely documented in the literature, therefore their study gains special interest.
In the north of this province, high levels of arsenic in drinking water were reported; however, removal interventions were scarcely documented.
The protection of low porosity stones, as marbles, from atmospheric deterioration is challenging and scarcely documented in literature in terms of evaluation of the performances of conservation treatments exposed to real conditions.
The evaluation of the factors associated with inappropriate use has scarcely been documented in our setting.
Studies have shown diverse strength of evidence for the associations between air pollutants and childhood asthma, but these associations have scarcely been documented in the early life.
In contrast, discrimination in children has been documented scarcely, but children are better at discriminating than at naming as compared to adults, and they perform like adults already at the age of 11 [38], [38].
If you were a Conceptual artist in the late nineteen-sixties and early seventies, it scarcely mattered what you did, as long as it wasn't much, and you documented it.
Outside - still cold, scarcely believable that it was May - the grim work of collecting forensic evidence and painstakingly documenting an atrocity was continuing.
