The phrase "also include a third" is correct and usable in written English.
It can be used when you want to add an additional item or element to a list or group that already contains two items.
Example: "The committee will review the proposals and also include a third option for consideration."
Alternatives: "add a third" or "incorporate a third".
The reforms, brought in under the last government, also include a third category for those whom officials think could do some work if they received the right help and support".
Clubs must also include a "third doctor" in the tunnel to assess any players with a head injury – rules that were implemented after Tottenham's Hugo Lloris was allowed to continue playing after he lost consciousness in a goalless draw against Everton in 2013.
A joint bid could also include a third party like Apax Partners.
The dyskinetic subgroups are choreo-athetosis and tonus-changing (dystonia) and also include a third transitional group, dystonia plus choreo-athetosis, in which neither dyskinetic sign is dominant.
Path plots can also include a third variable but are difficult to visualise in print, and so an animated GIF can be found in Additional File 6, which plots TFA scores on the third axis.
The proceedings also include a second "Terminator" look-alike, Adin Alai, a major hunk with the build of a young Arnold Schwarzenegger.
The consequences could also include a second Taliban emirate, a long, bloody civil war, and a sharp, destabilizing increase in Islamist violence, not only in Pakistan but also in India and elsewhere.
The Touch controllers will also include a second camera sensor.
Some financial modelers also include a fourth factor in their prediction models, a momentum factor.
The project will also include a first-of-its-kind consumer grip fitting studio, an amenity that will no doubt prove popular with the steady stream of golfers making the Pinehurst pilgrimage from around the world.
The rather pricey peripherals notably also include a second camera sensor to boost tracking accuracy, as well as an add-on mount to connect the controller to a Rock Band guitar.
