Gravendyck، M؛ Balks، E؛ Schroder-Gravendyck، AS؛ Eskens، U؛ Frank، H؛ Marschang، RE؛ Kaleta، EF (1998). "Quantification of the herpesvirus content in various tissues and organs, and associated post mortem lesions of psittacine birds which died during an epornithic of Pacheco's parrot disease (PPD)". Avian pathology. ج. 27 ع. 5: 478–89. DOI:10.1080/03079459808419372. PMID:18484032.
Gravendyck، M؛ Balks، E؛ Schroder-Gravendyck، AS؛ Eskens، U؛ Frank، H؛ Marschang، RE؛ Kaleta، EF (1998). "Quantification of the herpesvirus content in various tissues and organs, and associated post mortem lesions of psittacine birds which died during an epornithic of Pacheco's parrot disease (PPD)". Avian pathology. ج. 27 ع. 5: 478–89. DOI:10.1080/03079459808419372. PMID:18484032.