Ternero - sorry I can't help much but all my books and notes etc. are packed away in storage as I'm about to build a new house. Not sure if you mean can you take the prints you've alreay lith'd and feel are too dark and bleach and re'dev. in lith again - I think you can, but if not some-one will be sure to correct me! The best thing I like about the bleach/re-dev in lith process is that it's done with the light on which means you can pull the print from the lith dev. when you feel you have the right effect. Yes, this is just the usual photographic bleach , but is best used at a weaker solution than normal, as you don't want the bleach to work too fast, you need to be able to judge when to pull from the bleach when you have the detail you require. Without my notes I can only give you a guideline to the bleach/re-dev process. Firstly you have to create a print normally with the usual develop/fix/wash process - the only difference is that the print must be over-exposed (because of the future bleaching etc.) by at least half a stop to 1 stop. The next session is done with the lights on, soak the print, then bleach, wash well then into the lith developer, then wash and fix and the usual final wash regime. The best paper I've found do far is Foma 131 - haven't tried the Ilford fibre warmtone yet but Tim Rudman and others highly recommend it if you can't get hold of the Foma. You also need to have some Old Brown on hand from your previous lith session, this is added to the lith developer. You may find that the first 3 or 4 prints are awful but after that they just get better and better, I always print more 4 more prints than I need and just sacrifice these first prints. Sorry I can't be more exact with the chemical details but I'm lost without my notes, but don't forget to keep about a litre of the used lith developer to keep as Old Brown for the next lith session, it keeps for ages.
Good luck, Patricia