Kletzander, L., Musliu N., Smith-Miles, K.
Instance Space Analysis for a Personnel Scheduling Problem
Problem Instances 

Instances 1-20: Real-life instances
Instances 21-2000: Generated instances
Originally located at https://www.dbai.tuwien.ac.at/staff/musliu/benchmarks/

Instances 2001-6000:
Newly generated based on Instance Space Analysis