Kevin Carson is a contemporary mutualist and author of "Studies in Mutualist Political Economy". Contemporary mutualist Kevin Carson considers mutualism to be free-market socialism. Other classifications include mutualist/communal anarchism. Among early advocates of market socialism were the Ricardian socialist economists and mutualist philosophers. Nils-Udo seeks to offer a mutualist vision wherein nature as environment is an omnipresent backdrop. Extinction debt may also occur due to the loss of mutualist species. SSQ Insurance is a company with mutualist values whose shareholders are also its members. In North America at least, barn swallows frequently engage in a mutualist relationship with ospreys. Mutualist ideas found a fertile ground in the 19th century in Spain. The true "Zooxanthella" K.brandt is a mutualist of the radiolarian "Collozoum inerme" (Joh. Some schemes were based largely in the development of autonomous, mutualist provision of benefits.