The set of better quasi orderings is $\Pi^1_2$-complete

MATHEMATICAL LOGIC QUARTERLY

10.1002/malq.19950410309

WOS:A1995RP59400008

http://hdl.handle.net/11390/675417

info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-84981422029

http://onlinelibrary.wiley.com/doi/10.1002/malq.19950410309/abstract

metadata only access