[UNPUBLISHED]

Juan Ramon Perez appeals his conviction and 168-month sentence imposed by the district court 1 after he pleaded guilty to drug and money-laundering conspiracies. In a brief filed under Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), counsel argues that Perez’s sentence, imposed at the bottom of an advisory Guidelines imprisonment *442 range of 168-210 months, is too long. Following careful review, we conclude that the sentence imposed by the district court was reasonable. See United States v. Garnica, 477 F.3d 628, 631 (8th Cir. 2007) (per curiam) (in cases where there is no dispute concerning district court’s calculation of advisory Guidelines range, reviewing court must only determine whether sentence imposed by district court is reasonable).

Turning to the arguments raised in the pro se supplemental brief, we note that any ineffective-assistance argument must be raised in a 28 U.S.C. § 2255 proceeding, where the record can be properly developed. See United States v. Hughes, 330 F.3d 1068, 1069 (8th Cir. 2003). Perez’s other pro se arguments, to the extent they relate to his case, are refuted by the plea transcript. Cf. Blackledge v. Allison, 431 U.S. 63, 74, 97 S.Ct. 1621, 52 L.Ed.2d 136 (1977) (“Solemn declarations in open court carry a strong presumption of verity.”)

We have reviewed the record independently under Penson v. Ohio, 488 U.S. 75, 80, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), and have found no nonfrivolous issues. Accordingly, we affirm, and we grant counsel’s motion to withdraw.