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Harper JR, Harley A, Hackel DB, Estes EH Jr.Harper JR, et al. Among authors: hackel db.Am Heart J. 1969 Mar;77(3):411-22. doi: 10.1016/0002-8703(69)90198-7.Am Heart J. 1969.PMID: 5766727No abstract available.
Walston A, Hackel DB, Estes EH.Walston A, et al. Among authors: hackel db.Am Heart J. 1970 May;79(5):613-9. doi: 10.1016/0002-8703(70)90280-2.Am Heart J. 1970.PMID: 5444450No abstract available.