Are there any books or articles on voice per se, the ways of development, improvement, the process of sound creation etc.?
Geography of the Voice by Jo Estill is a book that gives very detailed information on the physiology behind singing. It also gives examples of simple physical actions (such as raising eyebrows and smiling) that put the muscular and other physical mechanisms behind singing into place. These methods teach you how to sing any style of music in a healthy way that won't damage your vocal mechanism (vocal folds).
www.estillvoice.com has all of their resources for sale online. There are companion cds that are very helpful to the process.
I was helped "The Zen of Screaming" is an instructional DVD by Melissa Cross.
You can order this DVD here https://www.melissacross.com/vocal_training_products.php or find it in any kind of torrent trackers or file hostings.