Two replications of the 1989 study confirming that women prefer older men and men prefer younger women. These papers use actual rather than preferred age gaps.

Sex Differences in Mate Preferences Across 45 Countries: A Large-Scale Replication (2020)
https://pubmed.ncbi.nlm.nih.gov/32196435/

Couples age discrepancies in a large-scale European sample: Evolutionary and sociocultural perspectives (2024)
https://doi.org/10.1111/pere.12579