There are several books/articles which explain in more detail the development and potential benefits of eeg biofeedback/neurofeedback. In addition, many research papers can be found on the internet.
Below are some further sources of information

The Old And The New By Siegfried Othmer PhD
- Symphony In The Brain by Jim Robbins (ISBN: 978-0802138194)
- Healing Power Of Neurofeedback by Stephen Larsen (ISBN: 978-1594770845)
- The Peniston-Kulkosky Brainwave Neurofeedback Therapeutic Protocol: The Future Psychotherapy for Alcoholism/Post-Traumatic Stress Disorder/Behavioral Medicine, Peniston, G.
- Child trauma, attachment and biofeedback mitigation.Pop-Jordanova N, Zorcec T
- EG signature and phenomenology of alpha/theta neurofeedback training versus mock feedback. Egner T, Strawson E, Gruzelier JH
- Anxiety change through electroencephalographic alpha feedback seen only in high anxiety subjects.Hardt JV, Kamiya J.
- Review of EEG biofeedback treatment of anxiety disorders.Moore NC.
- Evaluating the efficacy of a biofeedback intervention to reduce children's anxiety.Wenck LS, Leu PW, D'Amato RC.
- Biofeedback treatments of generalized anxiety disorder: preliminary results.Rice KM, Blanchard EB, Purcell M.
- Neurofeedback Training In Chronic Pain Associated With Post Traumatic Stress Disorder and Affective Disturbance: A Case Study, Ibric, V.L., Jacobs, M.S.
- Controlled EEG alpha feedback training in normals and headache patients (author's translation) [Article in German] Lehmann D, Lang W, Debruyne P.
- A retrospective, follow-up study of biofeedback-assisted relaxation therapy in patients with posttraumatic headache.Ham LP, Packard RC.
- Treatment of fibromyalgia incorporating EEG-Driven stimulation: a clinical outcomes study.Mueller HH, Donaldson CC, Nelson DV, Layman M
- Self-regulation of slow cortical potentials in children with migraine: an exploratory study.Siniatchkin M, Hierundar A, Kropp P, Kuhnert R, Gerber WD, Stephani
- Biofeedback of Left/Right frontal Alpha Power Difference (abs) J. Rosenfeld, et.al.
- Preliminary evidence that daily changes in frontal alpha asymmetry correlate with changes in affect in therapy sessions. Rosenfeld JP, Baehr E, Baehr R, Gotlib IH, Ranganath C.
- Operant (biofeedback) control of left-right frontal alpha power differences: potential neurotherapy for affective disorders. Rosenfeld JP, Cha G, Blair T, Gotlib IH.
- Alpha-theta brainwave neurofeedback training: an effective treatment for male and female alcoholics with depressive symptoms. Saxby E, Peniston EG.
- Frontal interhemispheric asymmetry: self regulation and individual differences in humans. Hardman E, Gruzelier J, Cheesman K, Jones C, Liddiard D, Schleichert H, Birbaumer
- Treatment of a depressive disorder patient with EEG-driven photic stimulation.Kumano H, Horie H, Shidara T, Kuboki T, Suematsu H, Yasushi M