Although by now a large amount of observational material is available, the implications of these observations are far from clear.


Contemporary Physics, Quasi-Stellar Radio Sources, Volume 8, Number 4, 1967 (p. 357)


Although by now a large amount of observational material is available, the implications of these observations are far from clear.

Although by now a large amount of observational material is available, the implications of these observations are far from clear.

Although by now a large amount of observational material is available, the implications of these observations are far from clear.

Although by now a large amount of observational material is available, the implications of these observations are far from clear.