la quinta, calif. — boseant-piper of indian wells has merged its accounting practice with peterson slater & osborne accountancy corp. cpa robert boseant, formerly the managing partner of boseant-piper, said the firm moved its operation to peterson slater & osborne to serve the entire client base of the combined firm. peterson slater & osborne, founded nearly 50 years ago, offers a variety of services, including litigation support, fraud detection, business valuation, loan finance consulting, irs representation and attestation services.