Original sentence: Paul Alfred Biefeld (Germany), was researched Brown's beginning in the 1920s and continued through the 1950s and 1960s by Brown and other researchers.The use of this electrogravitic propulsion effect was further explored during the publicized era of gravity control propulsion research, which included the United States gravity control propulsion initiative.This was thought by Brown to be different from purely electrostatic effects, which were already well-known in the early 20th century and do not involve any new physics.To forestall any possible misunderstanding about his devices, he termed these flying machines as ionocrafts.Unlike Brown, he believed that what he was seeing was a strictly electrostatic effect.de Seversky had in fact published a lot of his own  work in
Edited sentence: Paul Alfred Biefeld (Germany), was researched mainly during the 1950s and 1960s on the use of this electric propulsion effect during the publicized era of gravity control propulsion research, which included the United States gravity control propulsion initiative.This was thought by Brown to be different from purely electrostatic effects, which are well-known and do not involve any new physics.de Seversky had in fact published a lot of his related work in , and with the aim to forestall any possible misunderstanding about these devices, had termed these flying machines as ionocrafts