NMR spin-spin couplings of carbocations



 Hello,
 I wonder whether someone can point me to the
 recent experimental literature on NMR spin-spin couplings constants of
 carbocations. I am particularly, interested in ethyl
 cation (bot classical and non classical, if available).
 I require this information for comparison with theoreticaly
 calcualted results. Thank you in advance.
 Ajith