1. ETSI ETR 300-3 ed.1 (2000-02): ‘Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Designers' guide; Part 3: Direct Mode Operation (DMO)’. 2000
2. ETSI ETR 102 300-3 V1.2.1 (2002-01): ‘Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Designers' guide; Part 3: Direct Mode Operation (DMO)’. 2002
3. Dunlop, J., Girma, D., and Irvine, J.: ‘Digital mobile communications and the TETRA system’, (John Wiley and Sons, New York 1999)
4. Gray, D.: ‘TETRA advocate's handbook, from paper promise to reality’, (Looe, Cornwall 2003)
5. Barclay, L.: ‘Propagation of radiowaves’, 2nd(The Institution of Electrical Engineers, London 2003)