Chelsea talent adviser Piet de Visser believes their transfer policy is spot on. The Blues have managed to earn millions from selling players who have hardly - or never - played for the club in recent years.
De Visser believes Eredivisie clubs should copy Chelsea's model to strengthen their finances.
"I understand the Dutch clubs do not do this," he said in Voetbal International. "Porto and Benfica have become rich in this way, they pick up young talents, knowing exactly what is happening in Ghana and Colombia.
"Chelsea has earned in recent years more than a hundred million. Ajax, PSV and Feyenoord can do this too.
"The new Farfán and Gomes are roaming freely, you just have to send scouts in the right direction."