Final answer:
For short-term recruiting, temporal staffing agencies, employee referrals, and online job boards are the most useful sources.
Step-by-step explanation:
When recruiting for short-term situations, the most useful internal or external source is temporal staffing agencies. Temp agencies can provide jobs for workers while they are looking for permanent work. They can also serve as a clearinghouse, helping workers find out about jobs with certain employers and getting a tryout with the employer.
Employee referrals can also be a valuable source for short-term recruiting. Referrals from current employees can help identify candidates who already have a familiarity with the company culture and values.
Online job boards can be useful for recruiting short-term positions as well. Job search engines like Indeed, LinkedIn, and ZipRecruiter pull jobs from various employer websites and job boards, making it easier for job seekers to find short-term opportunities.