And these are designated on aeronautical charts by the letter R followed by a dash and a number.

它们在航空图上用字母 R，后面跟着破折号和数字来表示。

Similarly to the restricted airspace, however, these are designated on aeronautical charts by the letter P followed by a dash and a number.

然而，与限制空域类似，这些空域在航空海图上用字母 P 表示，后跟破折号和数字。