ack Machine. Cambridge University Press. p. 68. ISBN 0-521-68297-5. For valuable complements for the 16th and 17th centuries see Beatrix Heintze, Studien zur Geschichte Angolas im 16. und 17. Jahrhundert, Colónia/Alemanha: Köppe, 1996↑ Collelo, Thomas, ed. (1991). Angola, a Country Study. Area Handbook Series (Third ed.). Washington, D.C.: Department of the Army, American University. pp. 14–26. ISBN 978-0160308444.↑ Baynes, T. S., ed (1878). "Angola". Encyclopædia Britannica. 2 (9th ed.). New York: Charles Scribner's Sons. p. 45. ↑ Collelo, Thomas, ed. (1991). Angola, a Country Study. Area Handbook Series (Third ed.). Washington, D.C.: Department of the Army, American University. pp. 14–26. ISBN 978-0160308444.↑ Collelo, Thomas, ed. (1991). Angola, a Country Study. Area Handbook Series (Third ed.). Washington, D.C.: Department of the Army, American University. pp. 14–26. ISBN 978-0160308444.↑ Collelo, Thomas, ed. (1991). Angola, a Country Study. Area Handbook Series (Third ed