External sources lie outside an organisation. Here the organisation can have the services of:
(a) Employees working in other organisations;
(b) Job aspirants registered with employment exchanges;
(c) Students from reputed educational institutions;
(d) Candidates referred by unions, friends, relatives and existing employees;
(e) Candidates forwarded by search firms and contractors;
(f) Candidates responding to the advertisements, issued by the organisation; and
(g) Unsolicited applications/walk-ins.