TIMOPTIC-XE (timolol maleate ophthalmic gel forming solution). Accessed April 27, 2015 from: https://www.merck.com/product/usa/pi_circulars/t/timoptic/timoptic_xe_pi.pdf
TIMOPTIC (timolol maleate ophthalmic solution). Accessed April 27, 2015 from: https://www.merck.com/product/usa/pi_circulars/t/timoptic/timoptic_optsol_pi.pdf
BETIMOL (timolol ophthalmic solution). Accessed April 27, 2015 from: http://betimol.com/prescribing-information/
Timolol maleate ophthalmic. DRUGDEX System. 2015 Truven Health Analytics, Inc. Accessed April 27, 2015 from http://thomsonhc.com.