Tuuha, H., E.V. Tellervo & J. Taskinen. (1992). Ergasilid copepods as parasites of perch Perca fluviatilis and roach Rutilus rutilus in central Finland: seasonality, maturity and environmental influence. Journal of Zoology, London. 228(3):405-422, figs, 1-6.
Ergasilid copepods as parasites of perch Perca fluviatilis and roach Rutilus rutilus in central Finland: seasonality, maturity and environmental influence.