The phrase "a further three days" is correct and usable in written English.
It can be used when indicating an additional period of three days beyond a previously mentioned timeframe.
Example: "The project deadline has been extended by a further three days to accommodate the additional revisions."
Alternatives: "an additional three days" or "three more days."
Flintoff's team do not play for a further three days.
Last night officers were granted a further three days to question him.
After a court appearance, in which the officers claimed she had been drunk and attacked them, Beji was fined and spent a further three days in prison.
With both sides finally at the table, the Takeover Panel extended its Monday deadline for a firm offer from the bid consortium by a further three days.
There is no game scheduled for the preceding Friday so Capello will not name his squad until 4 October and the squad will not meet up for a further three days.
"On pouring day there were over 50 people involved pouring the chocolate into the mould and it took 10 hours to do, then a further three days to cool off".
Montague was suspended from work for a day, with a further two days held back barring another disciplinary issue.
The conference will begin with a two-day Hackathon on 18-19 October, followed by a further two days of on-stage interviews and panels.
Approximately 2 days were spent in downloading the 1680 records from Google Scholar, one day in downloading records from the other 3 resources and a further two days in screening all the citation records.
In Exp 3, the number of apoptotic OC was increased significantly in both vertebrae and tibiae on day 4 of the study and remained above control values for a further two days, but returned to control values in both the vertebrae and tibiae by day 9 of the study.
A few days later, a second letter arrives, postponing it a further ten days.
