TY  - RPRT
TI  - Formalizing the slow-roll approximation in inflation.
AU  - AR Liddle
AU  - P Parsons
AU  - JD Barrow
PY  - 1994
DO  - 10.1103/physrevd.50.7222
UR  - https://pubmed.ncbi.nlm.nih.gov/10017703/
ID  - 10017703
ER  -