Aug 15 (Reuters) - Ferrari team boss Fred Vasseur has spoken about his friendship with Lewis Hamilton as Formula One waits for the seven-times world champion to sign a new contract with Mercedes. Hamilton won Formula Three and GP2 (now Formula Two) championships with Vasseur's ART team in 2005 and 2006 before making a spectacular Formula One debut with McLaren in 2007. Hamilton, 38, was linked to Ferrari in paddock speculation earlier this year but the Briton has been clear he wants to stay at Mercedes. Vasseur said Ferrari's Charles Leclerc and Carlos Sainz could do better, as could the team as a whole in a so-far underwhelming season. "When I was at Renault, for certain changes you had to wait for the executive committee to meet, days and days went by.

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Persons: Fred Vasseur, Lewis Hamilton, Vasseur, Italy's, Hamilton, Ferrari's Charles Leclerc, Carlos Sainz, Red Bull, Leclerc, Charles didn't, Carlos, Ferrari, Loic Serra, Frenchman, Alan Baldwin, Pritha Sarkar Organizations: Ferrari, Mercedes, Hamilton, Formula Three, GP2, Vasseur's ART, McLaren, Italy's Gazzetta dello Sport, Briton, Renault, Thomson Locations: Qatar, Austin, Maranello, Bologna, London