Observers
MAUERSBERGER
WILSON
ROOD
BANIA
HEIN
LINHART
Link
Reference
MAUERSBERGER, R., WILSON, T.L., ROOD, R.T., BANIA, T.M., HEIN, H. and LINKART, A., "SETI at the Spin-Flip Line Frequency of Positronium," Astron. Astrophys. 306, pp. 141-144 (1996).
Search at Positronium line towards nearby stars and stars with IR excess that might be Dyson spheres.