DiChio, D.
, Natali, S.
and Kuyatt, C.
(1974),
Focal Properties of the Two-Tube Electrostatic Lens for Large and Near-Unity Voltage Ratios, Review of Scientific Instruments, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=620059 (Accessed May 9, 2026)