Rook and minor piece endgames, with pawns Where can I find resources on how to play these types of endgames?

I've done a google search, but all I came up with was repeated results for a Fritz Trainer dvd, and a similar, unanswered, question on chess.com. Silman and Dvoretsky's endgame books do not cover them.

I'm currently playing a correspondence game, and trying to come up with a plan before I blunder or drift into a worse position.
These kind of endgames often occur in practice, so even if it is difficult to give hard and fast rules about them, it is well worth spending some time studying them.

The book Practical Endgame Play - beyond the basic by Flear is quite decent and spends 4 chapters (111 pages) on the endgame Rook and minor piece vs Rook and minor piece. It is a relatively easy read.

Fundamental Chess Endings by Müller and Lamprecht (as mentioned in the comments) is an endgame book of high quality, but only has 9 pages on this particular type of endgame.

Another book I like is Endgame Secrets by Lutz. About half the examples in this book feature the material balance you ask about. This book is probably aimed towards stronger players as the analysis is very detailed.