The phrase "attested by numerous" is correct and usable in written English.
It can be used when referring to evidence or support from many sources or individuals regarding a claim or fact.
Example: "The theory is attested by numerous studies conducted over the past decade."
Alternatives: "supported by many" or "verified by several".
Extensive trade with Lebanon is attested by numerous vessels made during Pepi's reign and found at Byblos.
Old Persian, spoken until approximately the 3rd century bce, is attested by numerous inscriptions written in cuneiform, most notable of which is the great monument of Darius I at Bīsitūn, Iran.
The coregency is well attested by numerous monuments and artefacts where the names of the two kings parallel each other.
Coastal dwellers have long exploited these rich resources, as is attested by numerous fish remains (e.g., Badenhorst et al. 2011; Fleisher 2003; Horton and Mudida 1993, in press; Quintana Morales 2013; Quintana Morales and Horton 2014; Van Neer 2001).
The popularity of the new sequencing methods for gene expression is attested by the numerous recent publications and by the increasing number of submissions to public data repositories such as ArrayExpress (AE) (Parkinson et al., 2008).
The fascination of Lawrence's personality is attested by all who knew him, and it abundantly survives in his fiction, his poetry, his numerous prose writings, and his letters.
It is probable that the high content of plastic bags, that constituted numerous quite impervious surfaces, formed a high number of parallel slippery surfaces parallel to the valley slope as attested by outcrops along the scar.
The optimal parameter levels are attested by validation test.
The quality of the process was attested by Young's modulus and electrical conductivity measurements.
The applicability of method was attested by analysis of water samples yielding good recovery values (91.4 103.5%).
At increasing coverage the sulfate adlayer becomes more organized, as attested by the observed band narrowing.
