In some cases, different names were used concurrently for the same city.
These two systems were used in Tibet concurrently from about 1640 until 1959.
For the next two decades, the second and third series banknotes were used concurrently.
The new (orientation) numbers continue to be used concurrently.
However, this change has been gradual, with government reports concurrently using both imperial and metric units.
In North America, there are different systems that are used concurrently.
Some countries concurrently use the Gregorian and another calendar.
(Start here and use concurrently with each successive technique).
Both facilities are shielded or have marked danger areas to this explosive limit and may be used concurrently with other training.
Phenytoin may be used concurrently to prevent the seizures.