Path Integral Methods and Applications "introduction" to Feynman's sum-over-paths technique (which is the same as the path integral technique) http://xxx.lanl.gov/abs/quant-ph/0004090
Transactional Interpretation of QM John Cramer's take on the quantum measurement problem (suggested by davidcharleshobby ) http://mist.npl.washington.edu/npl/int_rep/tiqm/TI_toc.html