Coventry City have to keep their best players if they want to progress, says head coach Frank Lampard.
Defenders Milan van Ewijk, Jay Dasilva and Liam Kitching have all signed new undisclosed-length contracts with the Championship leaders, and Lampard believes it is a reward for their success so far this season.
"He's [van Ewijk] a very, very good player and a great player to work with from my point of view, as he's forever engaging with you, and I think there's more to come from him," Lampard told BBC CWR.
"Jay and Kitch have been mainstays of our performances this season. I'm happy when players feel they're improving, feel like they're enjoying coming to work and want to stay at the football club."
Coventry are one point clear of second-placed Middlesbrough and six points ahead of Millwall, who are third, as they seek a return to the Premier League after 25 years.
"If we want to improve, we have to try to keep players and improve [them] and keep working with them as much as adding them in, so it's great," added Lampard.
Coventry visit West Bromwich Albion in the Championship on Saturday (12:30 GMT).