20 USC 1087gg - Collection of defaulted loans: Perkins Loan Revolving Fund

(a) Authority of Secretary to collect referred, transferred, or assigned loans 
With respect to any loan
(1) which was made under this part, and
(2) which is referred, transferred, or assigned to the Secretary by an institution with an agreement under section 1087cc (a) of this title,

the Secretary is authorized to attempt to collect such loan by any means authorized by law for collecting claims of the United States (including referral to the Attorney General for litigation) and under such terms and conditions as the Secretary may prescribe, including reimbursement for expenses reasonably incurred in attempting such collection.

(b) Collection of referred, transferred, or assigned loans 
The Secretary shall continue to attempt to collect any loan referred, transferred, or assigned under paragraph (5)(A), (5)(B)(i), or (6) of section 1087cc (a)1 of this title until all appropriate collection efforts, as determined by the Secretary, have been expended.
[1] See References in Text note below.