Nelio Content allows you to add external calendars and show their events in the Nelio Content editorial calendar.
Note that this calendar import feature together with the calendar export feature allows you to have a unified view in one site of the posts you have in different Nelio Content calendars.
You will see that it is very easy: copy the public address in iCal format of the calendar you want to import.

Next, in the Calendars tab of Nelio Content Settings, paste it in the field provided for it and click on the “Add” button.

Once added, you will have it listed below.

And, if you hover the mouse over the added calendar, you will be shown the option to edit its name or delete the calendar.

Once imported, in the Nelio Content calendar you can now view the content of the added calendar.

Remember that in the right sidebar of the calendar, you can select/deselect which of the added calendars you want to display.