The phrase "ascertained from two" is correct and usable in written English.
It can be used when referring to information or conclusions that have been determined based on two sources or pieces of evidence.
Example: "The results of the study were ascertained from two independent surveys conducted last year."
Alternatives: "determined from two" or "established from two".
Hamilton's published relatively little during his lifetime, and though two volumes of lectures appeared after his death, his philosophical views can be adequately ascertained from three long essays that he wrote for the Edinburgh Review—"The Philosophy of the Unconditioned" (1829), "The Philosophy of Perception" (1830) and "Logic" (1833), subsequently republished in a collection of his papers.
The analysis included 1893 women with epithelial ovarian cancer ascertained from three population-based studies.
The determined systolic and diastolic pressures were ascertained from three readings using the mean value of the three.
From March 18 to July 31 , 2000 some 90 cases of serogroup W135 meningococcal disease were ascertained from nine European countries (the UK, France, the Netherlands, Germany, Finland, Sweden, Belgium, Switzerland, and Norway).
A total of 2088 BRCA1 mutation carriers, 841 BRCA2 mutation carriers and 3 carriers of mutations in both genes ascertained from eight centres participating in CIMBA were included in this study (Table 1).
Subjects were ascertained from four geographical regions assembled by a national network of acute leukaemia studies [ 12] and the majority of cases were included in a previous publication [ 6].
During 1972 73 in the region of North West England covered by the Manchester Children's Tumour Registry (MCTR), 91% of known childhood cancer cases were ascertained to the MCTR from Hospital Activity Analysis records (a predecessor of HES), 93% from the regional CR, and 93% from clinicians; 98 99% could have been ascertained from any two of these three sources (Leck et al, 1976).
Mammograms were ascertained from 1999 to 2001, two screening rounds prior to diagnosis.
As described previously (Chang et al. 2006; Ma et al. 2004, 2005), cases ≤ 14 years of age were rapidly ascertained from the nine major pediatric clinical centers in the study area, and controls, individually matched to cases on age, sex, race, Hispanic ethnicity, and maternal residence in the 35-county study area, were selected from California birth certificate files.
