Lewis itself should be a disambiguation b/c it's a last name and there is a T.W. Lewis article for example. Otherwise there is no single scheme for sources. Like Merlin has a Merlin (BBC), i.e. the broadcaster, others have the years like with BSG (that usually if there are more than one), other have (TV) in brackets. ETA: but I'd go with the original name, rather than the one with "Inspector" added.