Document 859
Hild, J. 1978. Biophenological Observation and Information Service in GAF, A Help for Birdstrike Forecast. Proceedings of the Bird Strike Committee Europe. BSCE13-WP20. Bern, Switzerland. 8 pages.
Hild, J. 1978. Biophenological Observation and Information Service in GAF, A Help for Birdstrike Forecast. Proceedings of the Bird Strike Committee Europe. BSCE13-WP20. Bern, Switzerland. 8 pages.
