Hi! Maybe I've not looked carefully enough but among the large amount of guide books available for Switzerland I could not find anything substantial with winter/mixed routes. Of course there are ice climbing guide books but I'm referring to gullies and goulottes...routes such as the ones you find on the Triangle du Tacul or on the Aiguille du Midi north side. So routes that are mainly on snow/ice/mixed but not purely 90° ice fall climbing. Those are just two examples, but I hope you get the idea.
If anyone has a suggestion where I could find such information please let me know!