medicines, which usually implies this can be implemented only after patents expiry and when generic or biosimilar medicines enter the market.: 193 internal reference pricing may reduce expenditures in the short term by incentivizing people to use the reference drugs at the reference price, but the effect on drugs with a higher price than reference and on health is uncertain. some countries, such as denmark which has a long history of using erp, switched to internal reference pricing.: 17 in 2016, out of 42 surveyed countries including who european countries, canada and south africa, 30 reported having internal reference pricing between generics, but only 15 also applied this policy to biosimilar medicines.: 193