In answer to a question of Long, Flapan constructed an example of a prime strongly positive amphicheiral knot that is not slice. Long had proved that all such knots are algebraically slice. Here we show that the concordance group of algebraically slice knots contains an infinitely generated free subgroup that is generated by prime strongly positive amphicheiral knots. A simple corollary of this result is the existence of positive amphicheiral knots that are not of order two in concordance.
"Infinite order amphicheiral knots." Algebr. Geom. Topol. 1 (1) 231 - 241, 2001. https://doi.org/10.2140/agt.2001.1.231