PPPs--twenty years and counting.
Sommer
Alfred
A
Abbott
Richard L
RL
Lum
Flora
F
Hoskins
H Dunbar
HD
D006801:Humans; D009885:Ophthalmology / Q000592:standards* / Q000639:trends; D010818:Practice Patterns, Physicians' / Q000592:standards* / Q000639:trends; D011787:Quality of Health Care