References

1.

van den Hout, W. B. The value of productivity: Human-capital versus friction-cost method. Annals of the Rheumatic Diseases 69 Suppl 1, i89–91 (2010).

2.

Brouwer, W. B. F. & Koopmanschap, M. A. The Friction-Cost Method. PharmacoEconomics 23, 105–111 (2005).

3.

Koopmanschap, M. A., Rutten, F. F., van Ineveld, B. M. & van Roijen, L. The friction cost method for measuring indirect costs of disease. Journal of Health Economics 14, 171–189 (1995).